Video games are, much like acts of play, easy to recognise but difficult to define. One early but useful account is Mark J. P. Wolf's. For him: “For a game to be considered a video game, one would expect the action of the game to take place interactively on-screen” (p. 16); he also observes that videogames have a range of both “imaging technologies” ( “light-emitting diodes, liquid crystal displays, vector graphics, raster graphics, precorded video imagery on laserdisc, compact disk, and DVD-ROM” (p. 19)) and “modes of exhibition” ( “mainframe, coin-operated arcade games, home videogame systems, hand-held portable games and game systems, and home computer games” (p. 23)). On this basis he argues that: “‘Computer games' . . . are most usefully seen as a subset of video games, due to shared technologies such as the microprocessor and the cathode-ray tube” (p. 17).

However, while it is possible to have a “computer game” without a video display, it is impossible to have a “video game” without computation. Above all else, a “game” is a program, a piece of software run on a computer, and in this respect the “computer game” is a subcategory of the “computer” as a medium and the “video” game is a “computer game” with a video display. Unfortunately, as Anderson, Holmqvist and Jensen's observe:

a computer is not just a medi um in the simple sense of a television set, a radio, a telephone. On the contrary, a computer is an extremely flexible and polymorphous medium. It is a multi-medium since the same physical machine can serve as a host for a variety of previously independent media-functions : It can simultaneously be an electronic mail system, a word processor, a database, a tool for advanced design, a paint box, a calculator, an electronic book, and a game-machine. (1993, p. 1).

The computer, then, is a “trans-medium” that may subsume or supersede other media. This notion is implicit in the rhetoric of “digital convergence,” in which the content of other media (images on celluloid or canvas, words in print) are digitised for display on a computer interface, and devices once distinctively associated with other media (film camera, paint brush, pen) are replaced by external devices that capture analogue information in digital form for the computer. However, while the computer may be a multi-medum, its ability to perform the function of other media requires some distinctive, generic capabilities: a computer comprises hardware that executes operations upon dynamic data displayed onscreen to a user who has a degree of ability to interact with this system using peripherals. The video game, played on a TV screen with a joystick and console, has a different interface from games played on desktop computers with a keyboard and mouse, and these differences affect the experience of play. Yet both are “computer games” in the sense that a computer is performing (computing) what we might call the “media-function” of a gaming platform.

While we might differentiate some games on the basis of the platform—principally, the degree of CPU power and the constellation of peripherals—games are increasingly ported to different platforms, such that game aesthetics may often lie more in software which has a generic adaptability to a computer perfoming the media-function of a computer game. Among the most well-known genres are action games, simulations, strategy games, adventure games and role-playing games, each of which might be said to form a relatively distinct subset of the media-function of the computer game. However, computer game genres were not defined on the basis of rigorous analysis of formal differences, but defined ad hoc and reinforced for marketing purposes. Not only have elements of the genres always overlapped, commercial and creative imperatives have meant that games are increasingly hybrid, drawing from aesthetics from a variety of genres and other media (Darley, 2000; Herz, 1997). While the gaming industry recognises between five or eight genres, with various sub-genres, Wolf produces a list of 43 genres. The issue largely depends upon the criteria by which one defines genre: while Hollywood cinema often discriminates genre in terms of, for example, iconography, structure and theme, computer games have distinctive interactive elements. Wolf's “generic types” catalogue game elements , not genres, and these elements are often combined in the genres accepted within the industry.

If we can speak of a video game "medium," then, seems to involve the media-function of the computer as a game, the routine constellation of its peripherals (a video monitor), and the constitution of software in defining the goals and rules of "games." To locate the medium simply in computer hardware would be too general (since the computer performs a range of media-functions, and because different genres utilise the computer as a trans-medium in different ways) while locating the medium in the software would be too specific (since there do seem to be some general components or aesthetics across many video games). The obvious way out of this impasse is some accommodation of the (potential) agency of a player who perceives these components as a video game. That is, an open definition might simply be that, whenever computer hardware, peripherals, and game programs come into a relationship we are in the presence of a video game, but that it is sometimes attitude of the player that finally determines the issue, since what may often not be considered a game (eg, playing with the cursor in Word, or some improvised fun between two people at the keyboard) may be engaged with as a game.

The underlying issue, of course, is that aesthetics cannot be defined simply in terms of the form or content of any medium or genre: the production of aesthetic experience emerges from a dialogue between aesthetic objects and those who engage with them, by reading, viewing, or “interacting”. The bridge between form, content and use may therefore be said to lie in the "codes" which govern the sense- and use-making of the “media-functions” of the computer game, its peripherals, and its genres. Codes in cultural are, of course, rules agreed upon by members of a shared culture which define conventional ways of making sense or use of "texts" (and which provide points of meanigful departure in making sense and use of them). Sufficient commonality exists in the cultural use of video games to provide a non-structural basis for defining video games as a medium: that is, video game exists whenever a person engages with hardware, peripherals, and software from the perspective of a (potential) player. Approaching gameplay in terms of "codes" has the advantage of maintaining some continuiity with Cultural Studies in general, and drawing from the rich theoretical background of that "discipline," while steering the issue away from a structuralist definition of either the video game as a medium, video game genres, or individual video games.