Some thoughts on game mechanics

 This piece may be expanded or amended over time.

All games have certain rules and constraints that limit how and what can be presented in them.  Yet across games that feature dialogue, interaction between Player Characters (PC) and Non-Player Characters (NPC), and combat there are certain design considerations that will vary from game to game.  Typically this gains the term of Role Playing Game (RPG) as either a game mechanic or as game elements.  Thus this is an examination of RPG mechanics although it will also, by doing so, cover discrete elements picked up by other genre games so as to add them to games that are not RPGs.

Levels
The idea of a PC or NPC 'level' is that they have a certain amount of power, skill, abilities and hit points that corresponds to their overall capability gained at a new level.  Higher level beings tend to be older, tougher and have more capabilities at their beck and call.  This is a concept that dates back to some of the earliest RPGs, like Advanced Dungeons & Dragons (AD&D) and levels were put under character classes with each class having its own set of attributes that can be gained as experienced is gained.  Thieves get better at Hiding in Shadows and Lockpicking, Spell Casters were able to cast more spells in a day and get higher level spells, and fighter types generally just got better at hitting things and dealing out damage, plus gained hit points at a faster rate than most non-fighter type classes.  Levels became an integral part of how RPGs are conceived well after that,  and that is an established way of doing things: as the PC progresses they get more skills, more abilities, more hit points and generally require higher level beings as opponents to face a challenge.  This requires that PC level be taken into account when drafting game scenarios and campaigns, and how much experience is gained and level advancement comes into play.  In such games it is typical to have a 'boss fight' that is significantly tougher than anything else in the scenario or campaign, which can present a real and even lethal challenge to the PC.

Are there game systems that are not tightly tied to levels?  Yes, there are.

A game like Call of Cthulhu (CoC) featured a non-level based system in which hit points were not gained but knowledge and skills improved over game play.  What this meant is that the PC was relatively static in their ability to take damage, so that no matter how good the PC got with a weapon (melee and ranged by and large) they were no tougher to kill than the ordinary NPC.  A couple of shots from a pistol could more or less reliably kill someone.  Armor wasn't that well distributed or used in the 1920's to 1930's setting, although some pieces of clothing did offer some resistance to damage, it couldn't be augmented nor changed to a higher value: a woolen trenchcoat was just a woolen trenchcoat.  Some creatures had armor or other resistances to taking damage or were just a bit tougher so as to reflect their different nature from that of normal humans.  This is actually not a bad system as it encourages thoughtful gameplay, research, and when an expedition must set out to delve into the unknown it had best be prepared to do so.  The healing and recovery system may not have been too well implemented, but it worked as a game mechanic.

In theory a game like AD&D actually accounts for all the HPs a character garners via leveling up as the ability to evade damage, evade that killing strike, or otherwise just be better at combat, while the actual HPs were the last few the PC has.  Basically the HPs a PC has at Level 1 are their 'real' HPs and all the rest are just combat ability related damage avoidance.  If all of those extra ones were stripped out, then AD&D would begin to mimic CoC or other games utilizing a similar system from Chaosium Games.  What those Chaosium Games did was reflect how much effort was put into boosting skills and abilities, and only those that the player worked on would advance, thus there was no 'class' for characters and no suite of skills and abilities one would get automatically over time.

A third way of keeping advancement but not utilizing levels started in the Champions game for creating Super Heroes, and was then expanded into the HERO game system.  This is a system where PC stats are not rolled up with dice but designed by the player.  A pool of base points was available to allocate between the PC's personal stats for their body, their skills and their powers, and that skill pool base generally allowed for certain types of PCs to be developed.  An individual with no training, no background and fresh off the streets might have 10 or 15 points to play around with beyond their universal base stats, and given the large number of places to invest those points, any character generated from that would be a normal person off the streets with a bit of training so they could hold down a job, and maybe a couple of decent character stats.  At 20 to 25 points characters start to be 'professional' types of individuals, very good at one skill, having more investment into character stats but generally not being all that notable otherwise.  At 50 points characters get into that range of highly skilled professionals, martial artists, surgeons, etc.  At 75 points characters start to get into the category best known for being inhabited by Super Spies or other top notch combat professionals.  At 75 points there are the first investments into an actual super power, albeit probably not a good one, and that would come with investment of points into that power beyond the skills and base character.  At 100 points comes the range of the third string Super Hero types and that is generally a good place to start a Super Hero game.

The HERO system didn't feature levels but, instead, had a system of direct experience point (XP) expenditure into anything the player wanted for their PC.  Those points could be accumulated over multiple sessions and the rate of gaining them was low.  Points are generally awarded on how well the player actually role played the character, completing a mission objective or showing innovative use of skills and powers during the course of the scenario.  Getting an award of 2 XPs was not unusual and 3 meant extremely good game play on the part of the player.  As the HERO system featured no cap on anything but, instead, utilized an exponential system were any attribute or power that was 5 points better was 2x as good (someone with a maximum human strength of 20 could lift twice as much as someone with 15 that could lift twice as much as someone at 10, and the base of 10 was the universal standard, untrained human lifting capacity) this meant quite a lot.  At 5 points another die for doing damage or with 3 points +1 to a skill roll (after it had gotten to the maximum of 3 dice for a roll using up one point for each die) and these could help other powers and skills.  One other thing that could be done with XP (as a house rule for the times I ran the games) is the burning of an XP to retroactively pass a skill check or take no damage from an attack, though the latter required an immediate reason why from the player within 15 seconds.  That steel cigarette case could only take that bullet if the character smoked, or that belt buckle that they wore somehow deflected that energy blast...and once a piece was used up like that it was marked on the back of the sheet so it could not be repeated.  Once you burned an XP it was gone, forever.  Those invested in a PC, however, could be allowed to undergo changes for good reasons or to set up a scenario a player had requested so they could change their character in a basic fashion.

From that the HERO game system did allow players to create PCs that did advance over time, became demonstrably better at what they did, but only allowed for them to be tougher, stronger, etc. if they invested points into it.  Skills, stats, powers and attributes all played together in a unified system, and no character was unbeatable, though learning how to beat them might take a long, long time.  Add to this the negative traits to get more points (ex. being Unlucky, being Hunted or having a physical problem) meant that players could get points but have a known (or somewhat hidden) deficit to their PC.

Thus the modern reliance of level based systems is more for how well it is known coming from the era of paper and pencil RPGs.  This allows for a certain framework of known level progression to be put in place as well as to make characters harder to damage or take more damage as they level up.  There are other ways of doing this, and in the era of computer based games much of the headache of something like the HERO game system (which typically required the first play session to be solely that of character design) could be reduced or nearly eliminated with a good framework built up around it.  Yet designing interesting and challenging game play that allows for multiple paths through it so that a PC of nearly any design could find their way through it requires a lot of work and it is that deep development investment that may stifle non-level based systems from coming to market.

So whenever a game features a 'level up' system it is doing so to let players know the type of game element or mechanic system that is in play not just for the players but for the entire game.  While a fanfare or bonus at a level up is a form of positive feed-back it is not the only way of doing things.  There is no such thing as a 'perfect' game system, but there are types of systems that suit certain game types in the RPG arena and those used the most tend to be easy to design and build out for a developer, although that can be at the expense of game play.

Play Balance
 How does a game balance difficulty for a player over time?  This is a hard thing to do and depends in large part on the game mechanics being implemented.  Level based mechanics will feature newer and nastier creatures, foes and environment while those with non-level based mechanics will keep start game challenges difficult throughout the game, and yet offer ways a player may adapt to the environment through their PC.  Both systems have strengths and weaknesses in the realms of combat and non-combat choices and interactions with NPCs.

Both level and non-level based game systems can feature skills that improve that are not combat related and will be relatively static throughout the game challenges, in that hard challenges will be presented throughout the game and building skills requires a trade-off between how one expends their PC's experience or level up grants over time.  Addressing one part of the game environment, say sneaking around, may mean not being able to advance as rapidly in other non-combat areas, say crafting or verbal interaction.  And in systems where the choice is broader than that, combat capacity may be in that balance so that deciding on where to expend points to improve skills will change the play type and style for a given PC.

In level based systems gaining skill with weapons, armor or equipment can often be augmented by other skills like negotiating with a gun pointed at someone or being able to combine stealth and combat into more damaging combat.  This sort of augmentation can be direct or indirect in that it may just do a direct increase to damage or defense, or it might give specialized moves or systems of attacks that are not garnered from just the base type.  Both are possible as well as separate types that work with each other, thus the level system must be tuned to acknowledge that the PC will gain skills and capabilities over time and address how foes or situations can remain a challenge without the game becoming a puzzle based one or one that is constantly boosting opponents to make them sponges for damage.  Here is where level based games become a bit unrealistic and can start to break immersive game play: by substituting in higher level opponents in situations that are basically just the base type but take more damage or just have a special attack or defense, the question arises as to why this constant chasing of levels is actually going on?  There are game genres and types where this makes perfect sense, like the further you go into an opponent's personnel roster or base structure, the harder those remaining become.  Out in the field the level based system can be problematical and require some ways to differentiate differences in difficulty without blatantly gating areas to certain PC levels.  This is typically done with tables of encounter types that are level weighted so that they reflect the PC's overall level, which can then garner disparities between hostiles that are in close proximity to each other.

An RPG with some action game elements is workable especially in combat or espionage based genres and they make perfect sense: the enemy has a structure that is either known about ahead of time or learned about through play and how the player adapts to that then guides where they go next.  This can be a subtle way of putting 'gates' into game areas so that players will learn that if they venture into an area too early they will not have a good outcome.  Still in an RPG that allows for multiple ways to approach a scenario, going in with weak combat skills but high skills in stealth, negotiation or speech, or with highly desirable crafting skills to then perform infiltration using what is available as they go are all available just as starters.  Knowing a higher-up or getting to one through bribery, stealth or other means (such as blackmail) are venues to get through areas where the combat may be instantly lethal and yet the PC has information that is too valuable to the enemy to do so.  Good action game elements do not over-rule the base RPG game mechanics and are just a sub-set of skills and abilities that bow to the larger genre.  A good RPG has multiple ways to crack hard nuts beyond brute force, and brute force may often be the last thing a player wants to do, not the first.

Conflict and Combat
 An RPG offers a framework for not just characters to run around in a game world, but has an existential set of conflicts going on in the background that has manifestations in the game world.  Those conflicts need not be military or even combat oriented: a struggle between two or more companies for gaining control of markets can offer just as much game play as one that features armed groups representing Nations, factions or other such large scale organizations.  The role of the PC can vary from that of being a world saving  hero to just an ordinary person trying to figure out just what the hell is going on in their life which has become a microcosm of the larger set of events.  There are many paths to a heroes journey even when the individual doesn't see themselves as a hero or is an actual anti-hero.  The actions taken by the player through the PC is then a reflection of the choices made to the events happening around the PC.

These are not just one-way actions, however, and taking actions will get reactions, though not necessarily equal and opposite.  Planning on the part of the player for the PC to get some expected reactions that then work to further the benefit of the PC's actions is not out of the ordinary in RPG environments: prodding a large organization in just the right way to get them to react in a way that is to their detriment is one way of starting to unravel a larger organization.  Thus conflict can range from a properly timed and sent memo to the destruction of facilities or eliminating key elements of the opposition's infrastructure.  It must also be noted that an opposition to the PC will form as the course of events begin to change, yet not all opponents are, of necessity, enemies and enemies may not even be permanent in all situations: teaming up with someone who you viscerally hate for both to survive an even worse disaster is not out of the question.  Be it a cop and a criminal working to escape a gangland shooting spree or soldiers from opposing armies teaming up to bring down a threat to both armies, the actual context is something that must be recognized as an intrinsic part of the game world.  Moving the world's destruction along to get an enemy to realize that you actually do want their help and are serious about it is something the player must work on as part of an RPG through the limits of their PC.

It is rare that RPGs do not feature a combat component or set of elements and this is something that must fit into the framework of the game, itself.  Skills in combat types and styles will determine and limit just what sort of responses a PC will have to the entire game world.  With that said there are a number of ways to approach how damage is dealt out and how to defend against it.  The types of damage that can be meted out varies by game and game world and can include but are in no way limited to: ballistic, physical (impact via melee weapons typically), energy, magical, radiation, and psionic/mental.  Each of these areas will tend to have specialized defenses that will fall into different categories and they are worth considering on the basis of those that are character based and those that are equipment based (though it is possible to gain some character based defenses from equipment).

Evasion/Avoidance of damage - This is typically a character based defense of just not getting hit and it works pretty well in most game environments.  Enemies have a known set of powers that are utilized in a known set of ways (this can be found out through direct encounter) and just plain not being there when the damage is delivered is a good way to go.  There can be equipment that will do this role as well, such as projecting PC holograms or duplicates, grounding out certain attack types, or even making the attacker clumsy or incapacitate their senses.  These tactics can be bolstered by the PC's abilities to enhance them and can moderate damage taken while avoiding it as well, so that dodging/evading through a combat environment becomes a worthwhile tactic.  Running from cover to cover also does this and utilizes the environment as a means to avoid damage and let the cover absorb it.  Concealment is simple hiding and can be very effective to allow for a surprise attack if the enemy doesn't figure out just where it is the PC is located. Concealment prevents no damage from being taken in and of itself and is a way to get an attack in when no one is expecting it or to avoid being found by searching.

Damage Resistance - Typically this is armor or some other sort of penetrable shield.  DR reduces incoming damage by a certain percentage that is usually capped for a category of damage type.  Damage that is resisted is calculated as a percentage of incoming damage and subtracted from that damage with the rest penetrating and game designers vary in that percentage maximum depending on setting, game design and play balance.  In non-layered defenses it is just that simple.  In layered defenses DR can serve as a primary reduction of incoming damage that is then further reduced by other types of defenses that are different from the DR.  In multi-layer defenses (beyond 2) a second layer of DR can also be added to further reduce the incoming damage after it penetrates the outer layers as a form of final defense, though it is typically relatively low in effect, typically <5%.

Damage Threshold - Typically this is a form of armor or other sort of penetrable shield with a threshold.  DT directly subtracts from incoming damage as a set amount, thus requiring incoming damage to reach the threshold of the DT to penetrate.  DT can be uncapped, but will suffer from armor piercing attacks that reduce the DT by a percentage (typically 50%) so a DT that starts at 10 will be an effective 5 versus a 50% armor piercing attack.  That is for non-layered defenses and is a simple concept to understand.  In a multi-layered defense DT can be put between other layers of defense or serve as an outer and usually relatively high buffer against incoming damage.  Still layering DT as a final layer gives a minimum threshold of exterior damage that must reach it and then surpass that threshold in order to finally get damage beyond the defenses.

Wear and Tear - This is an effect of how well defenses last over time before it is in need of repair.  Multiple penetrations against a defense may reduce its capacity to take damage or even break it entirely so that it is useless.  These effects can be a slow reduction in the defensive value or may offer better chances for a critical hit to bypass the defense entirely.  Additionally skill with precision in combat for weapons may allow for an attacker to penetrate the worn defenses based on a skill roll in combat.  Typically wear and tear is seen as a percentage figure that is then applied to incoming damage to see if the defenses will be applied or if the damage penetrates without defensive benefits.

Ablative Defenses -  This is a particular form of DT that isn't often used but is well worth mentioning.  AD is typically armor or other defense that has a high value beyond what any single attack can normally penetrate but is worn down by the value of the attack, itself.  Thus a high value AD will absorb damage and typically fall off or vaporize, thus reducing the remaining defense by that amount.  Here damage is absorbed, but unlike DT, the wear and tear is direct and immediate, not incremental and percentage.  AD can serve in a multi-layer role, typically behind a low value DT or DR that is used to blunt incoming damage and the rest then is applied to the AD.  The reverse can also be done, so that a DT or DR layer is behind an ablative defense, usually representing a last somewhat durable obstacle to incoming damage.  When AD is incorporated into a gaming environment it is usually a very cheap form of defense either to purchase or otherwise use, with the knowledge that it will go away very quickly and have a maintenance cost to it.  AD lasts until the last point is used up and then it is no longer there.

These are typical of the types of ways to deal with incoming damage across a wide spectrum of attack types, and they can also offer a platform for enhancements that will allow them to deal with other situations or be effective against some types of damage better than other types.  Based on the game environment some of these may be things that characters can do unaided via various skills or powers they have.  Even further some types of attacks may change category of damage so that defenses that would typically be useful against them are then either reduced or by-passed.  An example of this might be a form of telekinetic attack classified as a sonic attack, so that the attack now require another form of shielding that isn't covered by mental powers nor by standard defenses. A simple set of earmuffs used at a construction site may stop this entirely or a modified reflex roll may allow for a character to put their hands over their ears: it can be countered just not via normal combat means.

How damage is meted out isn't as important as what types of things can resist or stop it, thus much of the play style can be dictated by the player for their PC and honed into certain types of character build.  It is the damage consideration at a base level that is important.

There is another type of defense and that is against the environment of the game world, typically seen in 'survival modes' of games as opposed to pure survival games.  In temperate or hot climates this can mean having equipment that is made to slow the effects of water or humidity, or have coverings for the eyes, nose and mouth for desert conditions.  In cold conditions with snow the eye, nose and mouth are also essential for coverage, and a system of layered clothing can help to mitigate the effects of heat loss.  Unfortunately in the alternate mode for games this is usually not taken into consideration, and the resultant use of armor and equipment can feel clumsy at times.

As an example for a cold environment, a base layer of clothing is typically very light and serves to trap air that is warmed by the body.  A second and usually thicker layer is next, and offers some padding and protection against the cold as well as trapping air between it and the first layer.  A final layer is usually the heaviest and most resistant to letting heat out into the environment.  This should have a good first approximation in medieval fantasy systems where layered armor was the rule.  The basic roughspun tunic and pants, possibly with some form of socks served as a base layer to prevent chafing of the other layers.  A layer of padding or padded armor was next to mitigate damage from blunt weapons and generally serve as an intermediary for an outer armor, though padding itself could be used to that, though not by typical members of the military units.  Over that would go a final layer of chain mail, banded mail, scale mail on leather backing, or plate and chain mail, which would be the outer defensive layer that would take damage first and help protect against the lethal nature of attacks.  Outer armor, padding, base layer is the same for cold environments, thus a good RPG that recreates this type of setting will have this as a feature and make a 'survival mode' easy to implement.  Due to the 'fantasy' nature of most RPGs this is not the case.  Nor is it the case that the very same equipment used in a temperate or warm climate will then cause overheating and make dehydration severe.  What is proper survival attire for the arctic to sub-arctic is not the same as what is desired in swamps or desert, though troopers are typically forced to do that as the expense in equipment warrants it being used in all environments.  An integrated survival system will reflect this globally, and will also put the logistics concern of carrying multiple different types of garb for different environments into play balance.

In fact the 3 layer system also can be rendered into a DT, DR, DR formulation with added functionality given to the outer and intermediate layers.  As of yet there is no game that I know about in the computer gaming age that properly renders this.  While so many games focus on piercing or slashing damage, some of the worst damage is done by blunt trauma that can be transmitted through the outer defense and then applied to what is underneath.  Padding under an outer layer of armor, or even padded armor itself, is meant to lessen this impact by compressing while also expanding the area that the incoming force is applied to.  Blunt trauma is the stuff of fracturing bones, bruising muscles, causing bruises and inflicting internal damage to the body via burst blood vessels or trauma to organs.  Slashing vital parts with a sword or other edged weapons will cause damage that is direct penetration and relatively easy to spot: blunt trauma can cause damage that might not kill on direct impact but can still kill a foe in a short period of time. A multi-layer armor system will reflect the strengths of each layer on the defense, so that padding will also absorb some blood and can even be compressed by simply pressing on it to staunch immediate bleeding.

Even modern body armor has this concept in mind, with the wearer having regular clothes on as a base layer and then a multilayer armor that features wear and tear resistant outer cloth shell on multiple layers of resistant cloth, then a plate that suffers wear and tear, spreading the force of a projectile into causing fractures in the plate at the point of impact and deforming with a further layer behind that, all backed up by a final padded layer and resistant cloth.  When the projectile doesn't penetrate it still leaves a nasty bruise under the point of impact.  Due to the force of modern firearm projectiles and their ability to penetrate, suffering blunt trauma instead of piercing trauma is preferred.  This would be a system of DR (outer multiple layers), DT (inner plate and backing), DR (multiple inner layers) and a final low value DR for clothing.  How to change penetrating power of firearm projectiles into a number that makes sense for an armor system requires care and forethought, but can yield a viable system that should also have some ready use outside of that environment.

A good set of game mechanics should reflect the actual damage done in an RPG setting and be relatively easy to comprehend for the player.  Defenses honed to one sort of combat type or style may prove to be inadequate to another form of attack.  Ballistic cloth defenses, as an example, don't do so well against piercing damage typically seen by sword points being thrust through them, while a ballistic plate under it will certainly stop that form of damage.

Modern RPGs that aren't RPGs
When is an RPG not an RPG?  That is simple to answer: are the game mechanics focused on PC stats, skills, abilities and feature a framework of interaction with multiple branches of skills plus abilities for actions taken?  Take out any of those and the functionality of the RPG is then beholden to something else: RPGs use RPG game mechanics first and foremost, and then put a back seat to everything else.  Combat in an RPG isn't the main focus of the game, though it can be a time consuming activity as a part of it.  A multi-branching story with a wide spectrum of opportunities and the widest Player Agency to get out of the game what the player role-plays to put into then yield results determined by just how well that role is played.  What you do is determined by Who you are, and the situations a PC gets into are those that are required by Who they are and what that demands for moving the story forward.

A good RPG has a main story on simmer so that the more activity taken by the PC the more the heat will get raised, and the hotter the main story becomes.  The final results are based on the activities done: who the PC sides with (if anyone), what activities are taken at the direction or suggestion of the PC, weighting the scales of fate by doing as much as possible to get a desired outcome through activities, skills, stats and other bonuses, and then letting the chips fall where they may on this playing field.  Who you are determines what you do, and what you do will have consequences.  Game design requires this as a functional mechanic that tracks these activities and outcomes, and then starts off other events, activities and judgement by others to create a dynamic and interactive experience.

There are other framework elements that can be incorporated into this either as partial instances or merely a few elements so as to bolster the RPG mechanics.  Faction based games tend to rely heavily on interactions between groups and offers a ready method to personalize this form of mechanic or a few elements of it into an RPG.  Typically faction games do not go to much of a tactical level so that generic terms are applied to individuals or groups of individuals.  A leader may get a name, but the people he or she leads are generic: soldiers, thieves, spies, or any other category implemented to suit the faction based game.  Typically when this is lifted and put into an RPG environment the leader of the faction is the one who will be the source of changes for how the entire faction acts, yet all the lower level operatives will have names and back story as this is an RPG, not a faction based game.  Whenever a generic term is given to such an individual (ie. soldier, thief, spy, etc.) by a game it is with the intent of removing them from consideration for interaction...or is merely a way to hide the fact the PC can interact with them and get to know them.

Typically there are no interactive dialogues with the nameless individuals and only a generic per category response is given.  This is done so the game doesn't have to track each and every single individual as an individual as that means more record space, more thinking up of back story and more overhead in general.  Even with that, these non-interactive NPCs tend to be small in number even for organizations that should be quite large, as they are more set dressing than actually partaking of the story.  A good RPG will have a randomized set of backgrounds available in the 'fill in the blank' sort of way and suffer with such overhead to give the feeling there is more going on with an individual than is apparent.  Via interaction with the PC this can be sorted out pretty quickly, though it is a good idea to exhaust all the available background material for such an NPC just in case there is anything worthwhile that actually does pertain to the story.  Set dressing NPCs are used more in the style of game where the RPG elements are a back seat to something else that is the main consideration of the game design.

Here is where role playing is a necessity as the character that the player has set up will have varieties of skills, stats, and bonus abilities to get an idea if someone actually has a worthwhile background to pursue, and when those are lacking the indication that the player is on the right track but not skilled enough can either be given directly via dialogue choices that are indicated to not be available or useful at the moment, or via the way the NPC responds which can be in a leading fashion but to a topic that the PC cannot get to by not having the necessary prerequisites.  Both are valid and a good substitute for body language and other informal indicators used in real life circumstances: even with the best animations and renditions the game world still cannot satisfactorily mimic the real world and some individuals are just blind to such things as people, but understand it in a role-playing sense.

The modern RPG must indicate these things as there is no physical Game Master or other real, living individual to hand out the information: an RPG game must take that role on via its framework and then be designed so as to give out leading information that would typically be done via an individual running a face-to-face RPG.  There is no suitable replacement for a human GM (or person running the world in a non-partisan fashion), thus any RPG must come up with ways to give that information over to the player in a way that is consistent with game play.

There is an element of chance involved with this, and that must be properly reflected by either having skill, state or abilities gated so that information only becomes available with a certain skill level or have random chance take place in the background but with an indicator of a failure to the player, and both routes can be implemented simultaneously.  RPGs didn't start out with incorporating luck as a skill or stat, but offered ways to bias die rolls with equipment or other traits (thus a +1 sword generally gives a 5% better chance to hit with it and does one more hit point in damage, even when wielded by someone unskilled with it).  By the 1980's the concept of luck as being an integral part of how PCs work started to appear, as there are some people in life who are just plain lucky or circumstantially lucky.  Modern RPGs incorporate this to a greater or lesser extent, though they may obfuscate the actual mechanic in some way, of course.  If the game replaces the GM then it must also simulate lucky players of RPGs who would have lucky PCs, and if you have ever encountered such an individual in a face-to-face game setting you will have direct experience of this.  By regularizing and making it a game mechanic, everyone can now experience what such luck is like through their PC.

Modern RPGs that only incorporate one part of the RPG framework, say skills and abilities but not stats, then create a generic formulation of characters.  Stats are an integral reflection of the PC both for how the game world is perceived and how others perceive the PC.  Different forms of personal attractiveness be it charm, charisma, or just plain being likeable, plus the exact opposite of those, will influence other people with setting, personal preferences for the NPC and other factors coming into play for such interactions.  What the modern RPG can do is automate this and do the weighting in the background, yet the player via the PC should get an understanding of this mechanic via playing the game.  An NPC that has important information that they would not normally reveal during their work hours may be more approachable after them, particularly in their favorite venues for entertainment.  Learning that and doing it are integral to Role Playing, and a good game will have that available for every NPC the player can interact with.  In short NPCs are required to have depth of character to them, even those that the player may not like very much.  In fact finding out that NPCs have their own attitudes and might be more willing to help the PC out (although not always in ways the player wants) should form an undercurrent to the entire game world experience.  Very few games do this well or at all, and while one or two NPCs might have a deep back story, the vast majority of others do not.

Another failure for many modern RPGs is the 'it's not what you know, but who you know' network of interpersonal friends, family and other associates that NPCs should and indeed must have.  Most worlds do not feature this as it requires a lot of overhead to keep track of this form of interpersonal relationships between NPCs and for the PC to then become a part of those networks.  Becoming well connected should offer a variety of alternatives in stories, even those that seem to be highly combat oriented, as this network Friend Of A Friend knowledge can move in ways that are oblique to the direct forward driven form of story narrative.  Veering away from direct paths means developing skills and abilities, plus seeking out bonuses to help do that, which means having to work on-the-fly to deal with other, more direct forms of confrontation with antagonists.  These can be roadblocks of traps, surveillance or even other agents working within the FOAF network to find individuals that don't belong.  Via this method individuals who cannot be approached easily, if at all, by direct confrontation can be accessed by learning who their friends are and then following the FOAF network seeking to connect to their network.  This is an underutilized game mechanic and the few times anything like it are used, it is usually a simple one-step away deal of getting a close associate of the NPC that is critical to the story to then get the PC access to them.  That is unrealistic in many ways, although the lonely NPC who feels as if they aren't appreciated might succumb to it, they have probably experienced something like it before and require much more in the way of building trust than a simple meeting at a bar or some such.

Other game mechanics such as stealth, picking locks, breaking and entering, and the such are more easily implemented, though not necessarily well done in modern games.  How perceptive individuals are in a game world is something that must be replicated from the real world, which requires cones of vision, hearing depth of field, changes in vision ability in various lighting conditions, pinpointing sounds and the ability to catch motion at the periphery of the visual cones.  Additionally air currents and smelling should be a part of this, though it will vary based on the game setting, so that in worlds with much more complex and overwhelming smells this ability will prove to be of little use.  In general getting this information to a player and reflecting it in NPCs is difficult, and most games go with a general sensory hemisphere around characters, instead of incorporating the wider dynamics for senses so that there are overlapping zones of very good perception and much wider zones of poor perception.  This is something a GM can determine on the fly and weight almost instantly in a given situation and then say what the player perceives: one quick die roll ought to do it.  This must be done constantly in a computer game of the modern era, and while the processing amount is low, the ability to convey the complexity of responses are limited.  No game does this very well, though Stealth based games give a very good go at it but they are dedicated to the mechanic, and incorporating the full mechanic into an RPG would tend to swamp the game balance towards stealth.  Elements of the mechanic and utilizing basic shadows and camouflage or other means of blending into the scene can be done in a modern RPG though the number of elements will be, of necessity, limited.

From this, when analyzing a game the very first determination is the question of stats, abilities, skills and other character benefits that are available and if these form a reinforcing system so that skills based by good stats for that skill are reinforced, and if other abilities or benefits augment those skills.  A progression system that is intuitive and leaves leeway for the player to increase their abilities via a fine tuned methodology becomes a key point of being an RPG.  Shoving a single skill level point into a skill to alter it dramatically is not the same thing as working on it over time and finding other PC benefits that can then augment it.  Player Agency allows for how this happens, so that if a player desperately needs a single skill to go up quickly they can do so, but if they need a number of skills to go up incrementally they can also assign increases that way.  Anything that restricts Player Agency to bow to another game mechanic means that there are just RPG elements in a game, and it is not an RPG as a general rule with some exceptions.  A game that features combat or action mechanics will typically get the first part of a game genre: Shooter, Action, Stealth, Rogue and so on.  The term of RPG often gets tacked on as an afterthought so that game publishers can try to garner a wider audience for their game which is a disservice to the RPG genre.