I am noticing there are multiple genres people tend to end up mislabeling games under.  I figured that I would start a thread to discuss this, and also look at minutia arguments to me, that seem absurd. Feel free to agree or disagree here, and add your own.

Ok, onto the list (in no particular order, outside of recall):

1. Puzzle games.  I have seen the likes of classic arcade games, such as Pac Man get called "Puzzle games".  Just because a game fits on a single screen, with no scrolling, doesn't make it a puzzle game.  Same with it requiring some thought and strategy. 

2. RPGs.  Oh, one can go into several angles regarding this.  First, the TRUE definition of RPGs involves playing a role that isn't yourself, in a story.  Stat building isn't necessary for an RPG, but is usually the norm.  One has to beg whether stat-building alone is enough for a game to be an RPG.  A problem we run into here is that almost all videogames, outside of games that involve puzzles, have you playing a role, rendering the genre of RPG a bit meaningless.  However, what we normally accept as an RPG on videogames, is a videogame emulation of people playing D&D (or another paper RPG with stat building).  So, we have something oddball where a person plays the role of MORE THAN ONE CHARACTER at the same time, just so long as the party is upping it stats.  Again, the computer EMULATES a paper and pencil experience for players.  Again, this gets a bit ackward, because if you look at live action roleplaying games, you run into places where there is NO stat-building.

Another angle here is Zelda.  Zelda gets lumped into RPGs sometime.  It has character improvement through the collecting of items, but not really stat-building (Well, Zelda 2 had it).

3. First person shooter vs third person shooter.  I am not going to go and say people get this wrong, just that they argue that it is CRITICALLY important to separate the two.  As I see it now, the way decent shooters from Third-person view (aka like Gears or Uncharted) work now, it is more like your camera is further back in a FPS (except when aiming).  I end up ducking for cover, and aiming like a do in a FPS.  Of course, I get a better ability to jump and move around in third person view.  However, why the argument over Gears being "not in the same arena as Killzone 2".  Back in my day, a "Third-person shooter" was the likes of Robotron, Berzerk, or Smash TV. 

Of course, I could be off, or missed some, so feel free to add your own comments here.

RPG seems to be the catch all category for games these days. FFX and TES Oblivion are both considered RPGs yet their styles are like polar opposites. :p

It doesn't help that some genres (action, adventure spring to mind) don't have very good operational definitions.

With an RPG... well, almost every character centered game has some small sort of role playing (eg you play the role of Mario), and many now have some form of improvement, whether through leveling up, stat building, or power accumulation. I think oneof the big keys is really customization - with Zelda, you play Link, and your Link will be no different from my Link. This is different from Mass Effect, for example, in which we may play two very different Shepards (different race, sex, background, skills, powers and ethics).

dbl pst

Thinking more on this... Gaming genres are an artificial construct, so there is no natural way to categorize games, and there will be much cross-pollinating. Elements from a popular game will often be borrowed by a number of others, even if they have a completely different genre. If one were to actively categorize games by "genre" you would need to identify a number of variables. Here's the basic model I suggest:

1. Presentation: How do gamers see the game? There are two subsets to this:

a) Dimension: 2D, 3D or the always myserious 2.5D (4D, despite promises to the contrary, has yet to appear. No one seems interested in 1D).

b) Perspective: Single screen, scrolling screen, first person, third person, fixed camera, free camera, on rails, top down, etc.

2. Setting: What is the game world? (as with Perspective, these can be easily be blended ie - SF Horror)

a) None/irrelevant: Puzzle games

b) Contemporary: Set in a world somewhat modeled on the one we know and live in, give or take about 20 years.

c) Historical: Set at some point in the known past (Old West, WWI, Ancient Rome, etc)

d) Science Fiction: Ray guns, aliens, and psychic powers

e) Fantasy: Magic, swords, orcs and dragons

f) Horror: Werewolves and Vampires and Zombies Oh MY!

g) Cartoon/Classic Video Game: Mario, Sonic, Jak and Dexter

3. Gameplay: What are the gamers doing? This is what most of us think of as the game's genre. Games may borrow some gameplay elements from other genres (Sports sim, Action RPG, etc)

a) Sports: A simulation of a sports game, usually based in the real world.

b) Racing: A driving game. Typically broken down into Arcade and Sim

c) Adventure - Puts more emphasis on exploration and story telling than action (Zelda).

d) Action: Meant to keep the adrenaline running. Ninja Gaiden, God of War, etc

e) Shooter: A subset of action that has grown large enough to deserve its own entry. Many games have shooting elements, but true shooters put the emphasis on... shooting.

f) Stealth: A mutant offshoot of the action/shooter, which has replaced much (but not all) the action with sneaky elements

g) Sim: Simulates a real world activity (flying a plane, living life, running an amusement part, dating)

h) Strategy: Often a complex derivation of Chess and Risk. Main goal is development with an eye towards conquest.

i) Music/Rhythm j) RPGs - Player grows, develops and customizes a character or group of characters (most often against an epic fantasy setting).

k) Minigame compilations - Includes many short, often unrelated games with (often) minimal depth (if Multiplayer, called party game).

l) Puzzle - Emphasis on problem solving with minimal or absent characters, action and story.

m) Platformer - Emphasis on moving from one disconnected platform to another in order to travel through the game world. Three common subsets would be the puzzle platformer (Braid), skill platformer (Mario), and action (adventure?) platformer (Prince of Persia).

n) Survival - Typically a horror title (anyone have an exception?) in which ephasis is placed on survival rather than defeating enemies.

o) Point-and-click - a blend of puzzle and adventure game.

p) Exercise games - Thanks Nintendo...

q) Text based: Nearly extinct form of gaming from paleolithic era. Pioneered 0D gaming.

4. Community: Who plays the game? 1 player, 2 player, online, co-op, etc

I think between these four factors, you can pretty much describe any game.