There are countless descriptions of these genres by gamers, game designers, and the gaming industry, but these genres are not consistently identified . Computer Gaming World identifies six major genres—action/arcade, wargames, strategy, role-playing, simulations and adventure (Myers, 1991)—while PC Powerplay identifies five major genres—adventure/RPG, action, strategy, sims and sports games. Such classifications are not completely arbitrary, but neither were they defined after rigorous analysis of formal differences: they emerged ad hoc on the basis of experiments with new technologies and the convenience of marketing. The following draws from J. C. Herz's (1997) descriptions of eight major genres, and several sub-genres, observed within the industry and by players, and must be taken merely as a descriptive overview.

Action games are perhaps the most common genre, with subcategories based on structural differences, hence: horizontal and vertical scrolling platform games ( Terra Cresta ), platform climbing ( Maria Bros ), maze chase games ( PacMan ), and 3D first person shooters (FPS) ( Doom ). FPS have become the predominant kind of PC action game, and involve players negotiating a hostile virtual landscape and the accumulation of weapons and ammunition to destroy oncoming aliens, monsters, mutants, aliens, criminals and so on. FPS can usually be played single or multi-player, though the multi-player games are gaining prevalence. Multi-player games like Rogue Spear and the Half-Life modification (“mod”) Counter-Strike are generally collaborative, and games such as Quake 3: Arena and Unreal: Tournament also cater for teaming-up; however, many multi-player games are “deathmatches” that continue until only one player is left alive.

The standard simulations are single player, first person, “ pseudo-VR” (p. 29) versions of flying/driving a (usually military) vehicle (plane, helicopter, tank, submarine, spaceship) ( Apache Helicopter ). However, while simulations may be technically accurate in their representation of the sensitivity of controls and the effects of physics on movement, many incorporate options for a simplified interface and specific goals, such as military missions, which make them indistinguishable from FPS. Generally, the interfaces of simulations are as varied as the activities being simulated: they may be first, second or third person; real-time, turn-based, or response-based; simplistic or sophisticated; graphical and/or text-based. However, simulations of the dynamic management and development of a place (city, civilisation, ecosystem, planet) have given rise to the sub-genre of “world-building” games, such as SimCity , The Sims and SimEarth .

Strategy games encompass computer versions of board games (such as Risk and Battle Chess ), wargames ( Warcraft and Red Alert ), and so-called God-games ( Civilization and Black and White ) (p. 1997, 24-31). These games are characterised by (pseudo-) military strategy, usually involving analysing troop movements on a map, but have increasingly involved the management of resources, as in Knights and Merchants . The interface of strategy games is usually a top-view map, with units and objects that can be clicked upon to get additional information and options for deployment; often a text menu will be across the top or bottom of the screen. Multi-player games are usually played on a single map, whereas single-player games usually involve a series of battles on different maps in an extended campaign, such that the character may develop a long-term identification with a side, race, or units. Strategy games are usually turn-based, whereby players move all of their units before the next player takes their turn; if there is a computer-controlled player, there may be a pause when the computer AI determines troop movements, as in Heroes of Might and Magic . When strategy games are based in real-time, the duration of activities is not true to real-time but rendered in game-terms. For example, in Warcraft it may take a minute for a “town house” to be built, but only a few seconds for a “peasant” to be trained.

Adventure games (such as King's Quest ) and its subgenres of first-person, character driven adventures ( Phantasmagoria ), interactive murder-mysteries ( Deadline ), and point-and-click exploration games ( Myst ), are another popular genre. Adventure games may be third person or first person, but they are always single-player, and involve exploring an environment, navigating its difficulties or dangers, and manipulating it through the discovery, placement and/or exchange of objects and solving puzzles. While some adventure games have well-drawn characters, the player often identifies with the process of problem-solving, and most adventures can be seen as a series of puzzles, or one large puzzle. As with shooters, the whole screen is usually a window to the gameworld, and interaction involves clicking on items on the screen, sometimes to determine what items can be interacted with. This often involves the player experimenting until they discover the proper logical sequence for a mutually contingent series of activities, for example, the order in which to pull a row of levers. Interaction is not usually real-time or turn-based, but contingent upon the response-time of the player, such that the gameworld appears to be held in a temporal stasis or endless loop while the player considers their next action.

The other genres Herz identifies may be seen as related to, variations of, or subsets of the above four major genres. Fighting games, such as Tekken and Virtua Fighter , often have an oriental style of combat and are usually organised around an arena. The early fighting games were uniformly 2D with players fighting on a single plane; more recently they allow for the same kind of 3D immersion as FPS. Sports games, regardless of the interface, are usually a simulation of some kind of sporting activity, be it car racing, golf, or basketball. Although games of many genres utilise puzzles of one sort or another, puzzle games such as Tetris do not use puzzles as objects that stand in the way of the player-character, rather, the puzzle becomes the object of the game.

Computer role-playing games (CRPGs) are perhaps the most hybrid of computer games. The first computer game based on D&D —the “wriggling protoplasm of dungeons-and dragons tunnel adventure games” as Herz says (1997, p. 9)—was Hunt the Wumpus . This game involved the player choosing to move and shoot at each node of a maze: if the Wumpus was ahead, you killed it and won; if you moved next to the Wumpus, you lost. Hunt the Wumpus was superseded by Adventure (known as ADVENT, due to the limit of six letter file names), which was initially programmed in 1967 by William Crowther, on a mainframe machine in Stanford, then developed by Donald Woods and released on the ARPANET in 1976. The object of the game was “to explore subterranean caves, fight monsters, [and] plunder storerooms for treasure” (Herz, 1997, p. 11), though Reid argues that its popularity could also be traced to the fact that it offered a form of immersion which engaged the imagination and provided a form of escapism and the freedom to interact as one wished (1994, online).

Single-player text -based adventures—we might call them Single-User Dungeons (SUDs), given that were the precursors to today's MUDs—gained popularity with the rise of home computers, and the release of games such as Zork (1977) and Dungeon (DUNGEN). What generally distinguishes adventures from role-playing games is that while, with the former, characters may accumulate objects, with the latter, characters accumulate traits through initial character generation and character development during the game. As Aarseth (1997) observes, single-player text-based adventure and role-playing games were superseded in the 1980s by CRPGs that incorporated a rudimentary graphical user interface (GUI) based upon text-characters from the ASCII set, for example, ‘ z ' for a wall, and ‘@' for your character. These tended towards either a top-down view, as with Akellabeth , Rogue , Telengard and Moria , or 3D view, as with Labyrinth . The player generally controlled a single-player who acted in a fantasy-styled epic narrative, accumulating experience points and carefully managing inventories of weapons and items.

The release of such series as The Bard's Tale , Eye of the Beholder , Forgotten Realms , Might and Magic and Ultima marked the “classic” era of the CRPG. In these games, the player controlled not one character but a whole party, and the ASCII-character graphics were superseded by a proper GUI. These games had a 3D first person view of the “dungeon” or “wilderness” in a top corner window and a text window in which a description of significant items of interest, dialogue, and/or combat information was displayed. Portraits and basic information about the character(s)—usually four or six, with the game ending when the last character (or the main character) died—were displayed across the bottom or to one side of the screen. Additional information—top-down maps, 3D maps, character screens, quest summaries, health bars, active spell icons and so on—could be displayed over the graphics or text window, or on a separate screen, by pressing hot-keys (such as “C” for character sheet) or mouse-clicking on menu icons.

There have been exponential improvements in detail and realism of in-game engines and cut-scenes, the latter of which are often produced to the standard of blockbuster films. Indeed, the realistic, immersive 3D interfaces that emerged from first person shooters (FPS), from the original Wolfenstein 3D through to Unreal and Quake , are now standard across a range of genres, and the primary window or screen of many CRPGs and MMORPGs, such as Everquest , may be indistinguishable from this type. However, while this signals a movement away from the familiar CRPG interface to the 3D interface initially associated with FPS, what characterises the appeal and uniqueness of CRPGs is the combination of image and text and the visibility of the rule system in the form of numbers, charts, lists, and the use probability . In Balder's Gate , for example, there is the option of making the D&D rules visible or invisible, allowing for a limited choice between two genres, or two variations of the CRPG genre: the “classic” CRPG or the “action-adventure” CRPG.

However, with games now being ported from one platform to another, genres are increasingly mixed to create hybrid titles and i ndividual computer games are becoming difficult to identify as belonging to any one genre. This is evident in the playful, abbreviated, inconsistent and (seemingly) arbitrary use of generic terms in gaming publications. The PC PowerPlay (July 2000, Vol. 50), for example, includes classifications such as: Action/Strategy, Space Sim, 3D Shooter, Real Time Strategy, Driving Sim, Girl Meets Robot Action, Surrealtime Strategy, Jedi Power Battling, Cheesy Car Chase, Steampunk Roleplaying, Thirdperson Assassination, Unfeasibly Large Robots and First Person World Saving.

Such excessive description is an index of the particularity of each game's negotiation of various elements. The examples above seem to derive a generic type on the provisional inclusion of four defining elements. First, the form of interface(s), categorised as text-/ graphical-based; as 2D/3D; the way they represent space and/or time (real-time/surreal-time/turn-based); as first, second and/or third person; and/or as single-player/multiplayer. Second, gaming styles, categorised in terms of computer game genres (shooters, strategy etc) or general descriptions (action, battling, assassination). Third, print/film genre, categorised explicitly (horror, science fiction, fantasy, post-apocalyptic, mystery) or implicitly (robots, jedis, world saving). Fourth, especially in the case of simulations, the subject/activity being simulated, identified as a verb or noun (space exploration, driving, assasination, world saving) or adjective (“cheesy” car chase, “power” battling, “world” saving). A few descriptive terms, then, are often taken as representative of a game and used as a generic label, regardless of the explanatory imprecision.