Combat in Contextby Nick Montfort
What follows is a critical consideration of Combat, the cartridge originally included with the Atari Video Computer System. Atari introduced the VCS in late 1977. The system retailed in the United States for about US$200, the equivalent of about US$650 today. The console, model number CX2600 , came with two joystick controllers, two paddle controllers, a TV/ game switch box and a cartridge bearing product number CX2601 . The cartridge was Combat, a "game program" with 27 games, which were according to the included manual: variants of tank, tank-pong, invisible tank, invisible tank-pong, bi-plane and jet (Atari 1977). In the tank games, the two players move their joysticks left or right to turn their iconic tanks. Moving the joystick up causes the tank to go forward, while pressing the button fires a missile. Obstacles appear in some of the tank playfields and there are other variations in play. The two plane games are similar, but there are no obstacles in any of them -" only blocky, obscuring clouds in some versions -" and the planes always move forward. They are steered by moving the joystick up or down and go faster or slower if the joystick is moved right or left. The player whose tank or plane is hit the fewest times during a game, which lasts two minutes and 16 seconds, is the winner.
Combat is an important cartridge to consider for several reasons:
- For its own sake, as an important set of videogames played by millions
- Because it was the "default" cartridge for the Atari VCS and established expectations about what that extremely popular and influential system could do and how it should be used
- Because it sheds light on late-1970s video gaming
- Because, despite preconceptions about how the simplicity of Combat renders it unrelated to today's games, considering Combat can aid in understanding computer and video games from later eras - and from earlier eras, for that matter
Figure 1. Screenshots of a tank game and a bi-plane game from Combat.
At E3 in May 2000, Harmon Leon of the now-defunct gaming site DailyRadar.com set up a booth that featured an Atari VCS with a Combat cartridge plugged into it. The unit was wrapped in aluminum foil. Leon announced through his megaphone and using a hand-lettered sign that this system was actually a new game called CyberBattle 2000, and he enticed several conference attendees to play it (Leon 2000). A humorous review of CyberBattle 2000 appeared in DailyRadar.com after the conference, which read, in part:
[I]t's refreshing to see a videogame that pares down creativity, revealing the very essence of gameplay. The graphics engine, designed by ex-Rare and id programmers, manages to recreate the feeling of a battlefield, without overwhelming the player with unnecessary distractions. The glowing battlecraft reveal a subtle design ethic unmatched by any similar title. ... Musical influences have been borrowed from many sources, most notably Leonard Cohen and Philip Glass. The result is an ambient simplicity with a Mooglike analog vibe. ... that ... brings us to the plot - a plot so delicately strung that absolute attention must be paid as it unwinds delicate threads of intrigue and suspense. The twist at the end of the game is stunning. Cyberbattle 2000 revels in the fact that no other game will ever achieve this perfect balance between simplicity and style (O'Connor, 2000).
Today, many remember Combat fondly and some still play it once in a while, even when not writing academic papers about it. While the DailyRadar.com review was mockery (mainly of videogame reviewing), there are plenty of sincere contemporary reviews that are quite positive. One reviewer calls the cartridge a "true classic" and notes: "While the graphics can only be described as grotesque, Combat has great gameplay.... Besides Pong, Combat may be the ultimate two player game" (Langberg, 2003). Another writes, "This is the Charlie Chaplin of the gameworld ... Looks crap but is really, really good" (Bolton, 2000). There is some dissent - one reviewer writes, "I can't honestly say [it] has stood the test of time too well, not even as a two-player game" (Flying Omelette, 2003) - but most of those who have written about Combat recently have praised it.
Oddly, Combat has barely been discussed at all by critics or historians of the videogame. Scott Cohen's book, Zap: The Rise and Fall of Atari (1984) , does not mention Combat at all. Supercade: A Visual History of the Video Game Age, 1971-1984, includes only a one-inch-tall screenshot and the note that it "featured several variations of Atari's popular arcade game, Tank" (Herman, 2001). This analysis is an attempt to fill the gap in the current literature.
Levels of Combat, Contexts of Combat
To analyze Combat, I introduce a model that distinguishes five levels, all of which are surrounded by cultural and social context. My model is directly based on the seven-layer model introduced by Lars Konzack (2002), but it provides some significant refinements. It is worth emphasizing that in this new model the cultural and social context (which accounts for Konzack's seventh layer) is seen as surrounding and interacting with a game at all five of these levels, not just at the top. From bottom to top, I consider:
- Platform, the system on which a game runs. In the case of the Atari VCS this essentially corresponds to Konzack's first level, "hardware." However, distinguishing platform from other levels is not exactly the same as distinguishing hardware from software. A game that runs on Windows XP has that operating system, not just Intel-compatible hardware, as its platform .
- Game code, the computer program that realizes a game.
- Game form, the simulated world and rules of the game. Two different pieces of source code that have different compiled representations could both realize games that function and play identically. This level and the next draw a different distinction than do Konzack's layers of "functionality" and "gameplay"; those two are distinguishable in some ways, but are much more difficult to abstract apart and seem less interesting to consider separately.
- Interface, which sits between the player and the game form, connecting them. Chess games with identical rules and identical simulated opponents might present different interfaces: one a speech interface, one a two-dimensional (2D) view of the board, and another a three-dimensional (3D) view .
- Reception and Operation, accounting for what the player does in interpreting the meaning of the game; connecting the experience of the game to other experiences of gaming, art, literature or life; and actually playing - doing something to interact with the game via the interface. This level corresponds approximately to what Konzack distinguishes as "meaning" and "referentiality," two concepts that really cannot be abstracted apart in the way that an operating system and an application program can.
|o|| reception & operation||o|
|t|| game form||t|
|e|| game code||e|
Figure 2. A model for the analysis of computer and videogames, with five levels and surrounding context.
Lower levels enable and constrain what happens in higher levels. Players can only assign meanings to images if there are images presented in the interface, which can only happen if the game form affords something to present using images , which can only happen if that game form is realized in code, which can only happen if the code runs on a platform - specifically, a platform that supports graphics.
Although I believe this five-level model supports the analysis of computer games better than does Konzack's model, the most important point I hope to make here is that, whatever specific model is used, certain low levels that critics have neglected or glossed over can be important to understanding games, and these levels can be usefully explored by scholars.
Creating Context: For Two Players
The phrase on the catridge label "27 video games" is notable, but equally notable is the phrase "for two players." Combat requires two players, like the Pong games for home computers before it, like the arcade Pong, like Spacewar as developed at MIT in 1962 and like the analog computer tennis game that William Higginbotham showed in October 1958. Of course it is possible to run Combat when there is only one player or when there are no players, for that matter - but this hardly argues against it being a two-player game. The cartridge continued a social and competitive tradition in videogaming, and by being bundled with the VCS originally it helped to assert that play involving several people was the ordinary use of this system. (Atari expressed this idea in other ways, for instance, by running a television commercial that portrayed additional generations of a family joining in to play on the VCS, eventually resulting in a huge family crowd watching grandma and grandpa play.) Today, videogame consoles are sold with a single controller. This is no doubt done for revenue-enhancing reasons, but it certainly signals that something is different about the context of play �" perhaps that the two-player capability no longer needs to be overtly indicated, or perhaps that two-player games really are options that require additional hardware, and not the norm.
It would be very difficult to decide what genre Combat fits into, probably because any genre assignment would be anachronistic. videogames of different sorts did exist in 1977, although home video gaming was pretty much an all-Pong experience back then. The genre distinctions that are evident today developed later, as game forms became refined and conventionalized and as greater visual representational power was developed. But since the focus here is on Combat, this is not the place to speculate about which of these two factors was more important in the development of genres.
Platform: Racing the Beam
Since Combat ran originally on the Atari VCS, that platform is the one considered here. (It is also possible to play Combat today in an emulator, or on compatible systems such as the Atari 2600 Jr., the Atari 7800, or the Atari Flashback 2.0.) The VCS was designed to be situated on or near a television; the wood-grain plastic front of the case �" the design of which is imitated in the Flashback 2.0 �" made it seem, at the time of its release, more like a piece of furniture or a stereo component than like some piece of esoteric hobbyist electronics, such as a HAM radio or one of the Altair microcomputers that were available before the VCS. The two joystick controllers, each with one button, are used in Combat. The original VCS has six switches in front, including left and right difficulty and a game select switch used to choose from the 27 games. In Combat, the difficulty switches change the range of fire and, in the plane games, change the default speed of flight. Some configuration �" but not much �" was required to switch the TV over to VCS input, to insert a cartridge, to turn the VCS on, and to select a game to play. The system was ready for play fairly quickly �" there were no long load times, as with some more recent CD-ROM based console games. Playing games on the VCS was an activity that could be easily mixed among other living-room experiences such as watching TV and playing board games.
The main processor of the VCS is the Mostek (MOS Technologies) 6507, a low-cost version of a chip that was already low-cost: the 6502, the chip that powers the Commodore PET. The 6507 processor runs at 1.19 MhZ, as does the custom graphics and sound chip that was designed by Atari's Jay Miner, the Television Interface Adapter. The TIA provides for five moveable objects, control over the background color and stationary graphics. The VCS can directly address no more than 4KB of cartridge ROM, although bank-switching allowed larger cartridges to be developed. The system has 128 bytes of RAM �" not 128KB, but 128 bytes, due to the extraordinary cost of RAM at the time. Games ran from the cartridge's ROM, however; Combat certainly was not loaded entirely into this 128 bytes of RAM. This storage was only used for variables reflecting the game state, such as the player's score and the current bearing and velocity of their warcraft.
Programmers consider the VCS an extremely difficult platform, not only because of the austere system resources already described, but also because of the amount of video RAM that is available: none. Programming the Atari VCS means "racing the beam." A program running on the VCS cannot write to a screen buffer, as was the case, for instance, on all home computers of the era, but must proceed in sync with the drawing of the image on the television, generating each scan line as the electron beam crosses the screen to draw the current one. One modern-day VCS programmer writes: "I've never heard of an Atari VCS game that crashed and now I know why. There simply isn't room for the kind of sloppiness that allows a crash-level bug to slip through. If you're that sloppy, it won't even draw the screen" (Williams, 2001). One other feature of the platform is particularly worth mentioning here: The background is defined by a mere 20 bits that can either be duplicated or mirrored for the second half of the 40-pixel line. This is the technological factor that most directly accounts for the horizontal symmetry of the playing field in Combat. An idea of a fair playing field was no doubt the basis for this hardware decision in the first place, which was made in the context of earlier home and arcade videogames, games which generally had this sort of symmetry.
Game Code: Assembling Combat
Combat was developed from a core tank game (similar to the 1974 Kee Games Tank for the arcade, but without the mines that were part of that game) into a game program that offered advanced tank variations as well as bi-plane and jet games. The program was written in assembly language, as was always the case with commercial development on the Atari VCS. The early work was done by Joe Decuir as he was working on the hardware design of the VCS with Miner; development was completed by lead cartridge developer Larry Wagner (Decuir, 2003). The designers of early VCS games were never even identified by Atari �" they certainly were not prominently credited. Few people today, even among 8-bit programmers and VCS fans, know who the programmers of Combat are.
Critics have sometimes shied away from making comments on the code level because they do not have access to the source code of the game or because they lack expertise in the programming language the game was written in, but in many such cases there is still a great deal that can be said about how programming practices, tools and languages influenced the development of a game. Combat was fashioned to fit in 2KB of cartridge ROM. To provide an idea of how much information this is, the entire Combat program, in machine code, is shown in Figure 3. To provide an idea of what the source code was like, Figure 4 is a snippet of a disassembled and commented version of this machine code �" not the original source code, but something that should approximate what Wagner was looking at and working on as he finished Combat.
78 d8 a2 ff 9a a2 5d 20 bd f5 a9 10 8d 83 02 85 a6 b5 95 95 97 a9 1f 95 9b a9 00 95 9d 4c cb f3 88 20 a3 f1 20 32 f0 20 57 f1 20 72 f5 20 da f2 b5 9f f0 0d a9 04 95 15 a9 07 95 19 b5 9b 95 17 20 44 f4 20 14 f2 20 a9 f2 20 f2 f1 20 54 f0 4c 60 a4 85 b9 33 f7 25 88 95 19 b9 36 f7 95 15 18 14 f0 e6 86 85 2b a9 02 85 02 85 01 85 02 85 02 a9 00 88 30 04 69 0c 10 f9 75 8b a8 8a 0a 79 39 85 02 85 00 85 02 85 02 a9 00 85 02 85 00 a9 2b f7 95 17 60 a2 01 b5 30 10 2c 24 84 50 06 b5 9b 8d 96 02 60 a9 20 85 b4 85 02 85 2a ad 84 02 d0 c9 1f f0 22 f6 95 f6 97 f8 b5 a1 18 69 01 95 a1 fb 85 02 85 2c 85 01 ba 86 d3 a9 02 85 0a a6 dc d8 8a 18 69 fd 85 8a a9 ff 85 28 85 29 a9 00 95 85 02 ca d0 fb a5 dc c9 0e f0 52 a2 05 a9 00 85 19 85 99 85 9a 60 24 a3 10 03 4c 01 f5 b5 9f f0 de 85 df 85 02 a5 de 85 0e a4 e2 b9 c5 f5 29 f0 0a c9 04 f6 9f 90 04 a9 00 95 9f b5 34 30 07 a9 85 de a4 e0 b9 c5 f5 29 0f 05 de 85 de a5 df 85 00 95 9d 4c d6 f4 24 82 50 36 b5 9d d0 19 f6 9f 0e a4 e3 b9 c5 f5 29 f0 85 df a4 e1 b9 c5 f5 25 d6 9b b5 97 95 b2 49 ff 95 97 f6 97 b5 97 29 03 87 85 02 05 df 85 df a5 de 85 0e ca 30 0f e6 e0 d0 02 f6 97 4c d4 f4 c9 01 f0 0b c9 03 90 15 d0 e6 e2 e6 e1 e6 e3 a5 df 85 0e 4c 83 f0 a9 00 85 13 b5 b2 4c c8 f4 b5 97 18 69 08 95 97 4c d4 f4 0e 85 02 a9 05 85 0a a5 d6 85 06 a5 d7 85 07 a2 a9 01 95 99 f6 9d b5 32 30 04 a5 37 10 09 a5 8a 1e 9a 38 a5 a4 e5 b4 29 fe aa 29 f0 f0 04 a9 00 c9 02 90 09 20 08 f5 a9 03 95 e4 d0 14 d6 e4 30 f0 02 b5 bd 85 02 85 1b a5 a7 45 b4 29 fe 08 a5 06 b5 8b f0 0c d0 02 f6 95 b5 95 18 69 08 20 0f a6 45 b4 29 fe 08 a5 b4 10 02 49 f8 c9 20 90 04 f5 ca 30 03 4c 46 f4 60 8a 49 01 a8 b9 97 00 29 4a 4a 4a a8 a5 a5 38 e5 b4 e6 b4 ea 09 01 aa 29 0f a8 b9 27 f6 20 7c f2 a9 00 95 a8 95 aa 95 8d f0 f0 04 a9 00 f0 02 b5 bd 24 82 85 1c 30 0c b1 b5 d8 95 d6 60 a6 85 bd c6 f7 85 bb bd c9 f7 85 b5 85 0d b1 b7 85 0e b1 b9 85 0f e6 b4 a5 b4 49 bc a5 a3 4a 4a 29 03 aa a5 a3 10 0a 29 08 f0 04 ec d0 9c a6 d3 9a 85 1d 85 1e 85 1b 85 1c 85 1b a2 03 10 04 a9 80 85 82 a5 a3 0a 0a 24 a3 30 06 85 0d 85 0e 85 0f 60 ad 82 02 4a b0 13 a9 0f 85 85 02 85 84 29 80 85 83 a9 f7 85 b6 85 b8 85 ba 87 a9 ff 85 88 a9 80 85 dd a2 e6 20 bd f5 f0 60 bd cc f7 85 10 85 b5 bd d0 f7 85 b7 bd d4 f7 85 a0 02 a5 dd 25 88 c9 f0 90 08 a5 86 29 30 d0 02 b9 60 a5 a3 29 87 30 02 a9 00 0a aa bd 5d f7 85 a0 0e 84 dc a5 86 29 3f d0 08 85 89 e6 dd d0 02 04 bd 5e f7 85 05 a5 a3 29 c0 4a 4a 4a 4a a8 a5 85 88 ad 82 02 29 02 f0 04 85 89 d0 54 24 89 30 88 8d 82 02 49 ff 25 dd 85 d1 a2 ff ad 82 02 29 50 e6 80 a2 df 20 bd f5 a9 ff 85 89 a4 80 b9 d8 08 d0 04 a0 10 a2 0f 86 d2 a2 03 b9 65 f7 45 d1 f7 85 a3 49 ff d0 04 a2 dd d0 ea a5 81 f8 18 69 25 d2 95 06 95 d6 95 d8 c8 ca 10 ef 60 a9 00 e8 01 85 81 85 a1 d8 24 a3 10 06 e6 85 50 02 e6 85 95 a2 d0 fb 60 0e 0a 0a 0a 0e 22 22 22 22 22 ee 20 25 f5 a9 32 85 a5 a9 86 85 a4 24 a3 30 12 85 22 ee 88 ee ee 22 66 22 ee aa aa ee 22 22 ee 88 a5 85 11 a9 08 85 96 a9 20 85 20 85 21 85 02 85 ee 22 ee ee 88 ee aa ee ee 22 22 22 22 ee aa ee 2a 60 a2 01 b5 a1 29 0f 85 d2 0a 0a 18 65 d2 95 aa ee ee aa ee 22 ee f8 f7 f6 06 06 06 16 17 18 e0 b5 a1 29 f0 4a 4a 85 d2 4a 4a 18 65 d2 95 e2 19 1a 0a 0a 0a fa f9 f8 f7 f6 f6 06 16 16 17 18 ca 10 e1 60 24 83 50 04 a9 30 10 02 a9 20 85 b1 19 1a 1a 0a fa fa f9 e8 e6 e4 f4 04 14 24 26 28 a2 03 20 54 f2 ca 20 54 f2 ca b5 8d 29 08 4a 4a 2a 2c 1c 0c fc ec ea c8 c4 c0 e0 00 20 40 44 48 86 d1 18 65 d1 a8 b9 a8 00 38 30 01 18 2a 99 a8 4c 4f 2f 0f ef cf cc 00 00 80 80 84 20 88 88 92 00 90 0d b5 ac 29 01 0a 0a 0a 0a 85 b1 20 54 f2 48 a4 a4 a9 52 aa aa d5 aa da da db 6d ee ee 00 ca f0 d7 60 f6 ac b5 95 29 0f 18 65 b1 a8 b9 f7 fc fc 38 3f 38 fc fc 1c 78 fb 7c 1c 1f 3e 18 19 f5 85 b0 24 82 70 13 b5 95 38 e9 02 29 03 d0 0a 3a 7c ff df 0e 1c 18 24 64 79 ff ff 4e 0e 04 08 b5 ac 29 03 d0 04 a9 08 85 b0 a5 b0 95 20 29 0f 08 6b 7f 7f 7f 63 63 24 26 9e ff ff 72 70 20 98 38 e9 08 85 d4 18 75 a4 24 a3 30 04 e0 02 b0 10 5c 3e ff fb 70 38 18 38 1e df 3e 38 f8 7c 18 60 c9 db b0 04 c9 25 b0 08 a9 d9 24 d4 30 02 a9 28 70 78 ff 78 70 60 00 00 c1 fe 7c 78 30 30 30 00 95 a4 e0 02 b0 02 95 25 60 a9 01 25 86 aa b5 95 03 06 fc fc 3c 0c 0c 02 04 0c 1c fc fc 1e 06 10 95 0b 29 0f a8 24 83 10 02 94 97 8a 49 0e aa 98 10 10 38 7c fe fe 10 40 20 30 38 3f 3f 78 60 40 0a 0a 0a c9 3f 18 30 03 38 49 47 a8 b1 bb 95 bd 60 3f 1f 1e 1e 18 18 00 83 7f 3e 1e 0c 0c 0c 00 90 02 88 88 c8 ca ca 10 f3 60 a5 8a 38 e9 02 90 8e 84 ff ff 04 0e 00 00 0e 04 8f 7f 72 07 00 10 2b 85 8a c9 02 90 24 29 01 aa f6 95 b5 d8 95 d6 36 2e 0c 1f b2 e0 40 24 2c 5d 1a 1a 30 f0 60 18 a5 8a c9 f7 90 03 20 08 f5 a5 8a 10 0e 4a 4a 4a 5a 7e 5a 18 18 18 78 34 36 5a 78 2c 0c 06 0c 08 95 19 a9 08 95 15 bd fe f7 95 17 60 a2 01 ad 82 6c 70 b8 dc 4e 07 06 38 10 f0 7c 4f e3 02 00 00 02 85 d5 ad 80 02 24 88 30 02 a9 ff 49 ff 29 0f 0b 16 00 10 00 ff 01 11 01 ff 0f 1f 0f 50 5f 51 85 d2 a4 85 b9 0f f7 18 65 d2 a8 b9 12 f7 29 0f ff 30 3f 31 ff 70 7f 71 90 b0 70 ff 91 b1 71 ff 85 d1 f0 04 d5 91 d0 04 d6 93 d0 0d 95 91 a9 0f 9f bf 7f 08 02 02 02 03 08 1d 05 00 00 00 00 00 95 93 a5 d1 18 75 95 95 95 f6 8d 30 1e b9 12 f7 00 00 00 00 00 00 00 1d 1d 16 16 0f 0f 00 00 00 4a 4a 4a 4a 24 d5 30 23 95 8b 0a a8 b9 37 f6 95 00 00 00 00 00 00 12 10 10 0c 0c 07 07 00 00 01 a8 c8 b9 37 f6 95 aa a9 f0 95 8d 20 80 f3 ad 80 01 00 03 27 03 ea 3c 82 44 32 2c 8a da 80 9c da 02 4a 4a 4a 4a 06 d5 ca f0 9c 60 38 e5 85 10 d8 3a 64 a8 da 4a 08 04 00 0e f0 10 10 10 10 10 10 a5 a3 30 08 29 01 f0 04 a5 db 95 d6 b5 99 f0 27 10 10 10 10 10 ff 00 00 00 38 00 00 00 60 20 20 b5 d8 95 d6 b5 99 c9 07 90 14 24 d5 10 04 c9 1c 23 ff 80 80 00 00 00 1c 04 00 00 00 00 ff 00 00 90 0c c9 30 90 1f c9 37 b0 21 24 83 50 1d a9 00 00 00 00 00 00 00 00 00 00 00 07 1f 3f 7f ff 00 95 99 a9 ff 95 28 60 24 88 10 04 b5 3c 10 37 20 00 00 00 00 00 00 00 60 20 21 ff 00 00 00 80 80 10 f4 4c ae f3 20 10 f4 4c de f3 b5 9f f0 0a 20 80 80 00 00 00 07 4f cf 8f f6 f6 f6 75 75 75 9a 10 f4 a9 30 95 99 4c de f3 b5 99 20 00 f3 a5 86 81 99 aa 9d 8d 99 b6 9d 24 28 08 20 00 48 40 54 29 03 f0 0c 24 84 70 0a 24 82 50 04 29 01 d0 02 58 25 29 49 55 59 a8 88 98 90 a1 83 e8 c8 e0 c0 d6 99 a9 00 f0 be a9 3f 95 99 38 b5 a4 e9 06 95 e9 e2 c1 ff 00 00 00 00 00 00 00 00 00 f0 0f 11
Figure 3. The entire 2KB of machine code that is the Combat game program. (C) 1977 Atari.
; ------------------------------------------------------------ ; ; Video OUT -- THE KERNAL ; ; We start with the score, then we render the playfield, players, ; and missiles simultaneously. All in all, an average day for a VCS. ; VOUT LDA #$20 STA ScanLine ; We're assuming scanline $20. STA WSYNC STA HMOVE ; Move sprites horizontally. VOUT_VB LDA INTIM BNE VOUT_VB ; Wait for INTIM to time-out. STA WSYNC STA CXCLR ; Clear collision latches STA VBLANK ; End vertical blank TSX STX TMPSTK ; Save stack pointer LDA #$02 STA CTRLPF ; Double, instead of reflect. LDX KLskip Vskip1 STA WSYNC ; Skip a few scanlines... DEX BNE Vskip1 LDA KLskip CMP #$0E ; "No Score" value of KLskip BEQ Vmain
Figure 4. A small part of a commented disassembly of the Combat code. The line with the comment "Double, instead of reflect" is setting up to display the top of the screen, where the score is shown. Unlike the playing field, which is reflected, this part of the screen is doubled. Disassembly and comments by Harry Dodgson, Nick Bensema and Roger Williams. The entire file is available at http://www.atariage.com/2600/archives/combat_asm/dicombat.asm
Although the VCS was exceedingly difficult to program, understanding a program like Combat �" particularly a thoroughly commented program like this disassembly of Combat �" is actually not difficult. While it requires attention, it does not require a computer science degree or a college education of any sort. Assembly language for the 6507 provides a very small number of primitive operations, and programs mostly load values from memory, store values to memory and do some simple arithmetic. The machine code and the sample of the assembly code provided here are not intended to bewilder, but to show that there is not a tremendous amount to understand, and that the complete game code of Combat and other VCS cartridges can be fully comprehended by dedicated scholars.
The code and its context suggests the following: The difficulty in devising a good Atari VCS program is probably part of what led programmers to first create an enjoyable game with simple elements, and then to build on this by allowing 27 substantial but straightforward variations on these elements. Simple as Combat may be, the most basic structures of the game (shared by all variants) occupy a good bit of the cartridge's 2KB by themselves. Creating additional variants was a more feasible option, once the timing for a single variant had been worked out, than was enriching the experience through additional visual detail, by making subtle rule changes that are only seen in special cases, or by creating some extreme variation in game elements.
Although a similar pattern is seen in other early cartridges such as Decuir's Video Olympics, it was not the rule in later Atari VCS game programs. After programming tools had been further refined, and once more memory was available to cartridge programmers via bank-switching, and once a host of tricks and techniques were available in existing examples of code, visual detail rather than game variations would be added as a way of enhancing some games �" such detail can be seen in Off the Wall and Road Runner, for instance. So the approach of Combat is not inherent to the platform. It results from the nature of this platform in the early context of VCS programming.
Game Form: 27 Video Games
The chart provided in Figure 5 (taken from the Combat manual) explains the 27 games on the cartridge. It may not be obvious that these should be thought of as different games. In a very offhand way, it would be possible to justify calling these different games by observing that some people are skilled at certain ones but can easily be defeated when playing others. There is also a formal justification. As the chart indicates, important formal elements of these games are varied: the type of fire is either a straight missile, guided missile or machine gun; hits can be direct, off the walls or either; the battlefield can be open, one of two mazes or a wrap-around sky with or without clouds; and, reading down, the nature of the vehicle (including its visibility and default velocity) can vary as well. To further increase interest, five of the plane games provide one or both of the players with multiple planes flying in formation; they fire multiple missiles but also provide a larger target.
Figure 5. The 27 games. (C) 1977 Atari. Scan courtesy of AtariAge.
Espen Aarseth (2001)identifies Quake III as being a game platform, a way of playing games such as capture the flag and deathmatch, rather than being a single game itself. Off the computer, there have long been game systems, such as a standard deck of playing cards or the more recent Icehouse set of colored, stackable, pyramidical pieces. Each such game system provides materials that players may use to play many different games (Hale-Evans, 2001). Combat is neither an open-ended platform like Quake nor a game system like the Icehouse set, but it is also not just a game. Reasonably, the manual calls it a "game program" that offers 27 games. These 27 games share elements (and, obviously, code) and are arranged thoughtfully, in categories and also with a simple variant first. Game 1 is fun and a good introduction to Combat, but as soon as a player starts toggling the "select" switch, the other games advertise themselves visually as more complex and worth playing. Combat provides a good way for game critics to see how difficulty and enjoyability can vary when only one element, or a small number of elements, changes.
Interface: Close Connection
Since a great deal of new media criticism has the interface as its focus, or often, its obsession, the interface of Combat will not be discussed in much detail here. Giving or withholding information from the player is part of game form; the invisible tank games demonstrate this quite clearly. The interface only deals with the different ways that the same information may be presented, and the different ways that the same type of control data may be input by the player. Even in the seemingly simple system of Combat, there were some interface choices to be made, as a hack of this cartridge demonstrates. Paul Slocum's Combat Rock cartridge functions identically to Combat visually and in terms of game form, but all the sound effects in the original cartridge are replaced by a soundtrack. The cartridge repeatedly plays "Rock the Casbah" by The Clash. This does highlight something interesting about Combat: that the interface provided is almost purely devoted to conveying information about the game form in as direct a way as is possible, without decoration and without use of or reference to existing media.
Reception and Operation: Death and Stories in Combat
At the top level, that of reception and operation, there are a few questions that might seem only amusing, but are worth considering: Is Combat violent? Is Combat narrative, or dramatic? What story does it tell? These last two are the sorts of questions that were asked by the DailyRadar.com reviewer, but there is some use in trying to take these questions seriously.
Combat is violent; it depicts warfare and death, albeit in a very abstract way. The Atari VCS platform did seem capable of representing violence that is offensive to some people, as the reaction to the 1983 Wizard Games title The Texas Chainsaw Massacre demonstrated. But the violence in Combat is not only very stylized visually, it is also formally impermanent: a tank or plane simply spins when it is hit as the action stops for both players. This sort of "death" is more reminiscent of a game of tag than of warfare. The player's vehicle is not even destroyed and regenerated elsewhere on the screen; it simply seems stunned and ends up in a different orientation. This may go some of the way toward explaining why people generally look and act like they are having fun as they play Combat, and do not look or act like they are murdering anyone. Interestingly, bystanders in Grand Theft Auto: Vice City recover from being killed much as do the tanks and planes in Combat, although this is seldom pointed out in discussions of that game's violence.
There are no signs that it will prove useful to view Combat from a narrative standpoint, although the program does depict events that are connected by time and causality. This article has, so far, avoided any mention of movies or novels, and avoiding these is not difficult �" on the contrary, it would have been rather hard to relate Combat to Tank Girl or the silent film Wings in any useful way. Combat might somehow be tortured into confessing a story, but what it mainly does is facilitate a particular type of competition, providing an apparatus and context for play, a computer-mediated way of interacting with another player rather than a digital vehicle for an expressive message. It is difficult to see the game program as related to a war movie �" the illustration on the cover of the manual might be related, but that is part of a paratext. On the other hand it is easy, and helpful, to see a relationship to billiards in the tank-pong games (particularly the ones in which an indirect hit is required) and to see the relationship to games like target shooting, catch and tag.
It is also useful to recognize that Combat is related to early recreational computing, including playful programs that are not videogames, and to programs written for systems with very limited resources. Just as the extreme, formal difficulty of composition suggests some sort of connection between the Oulipo and the troubadours, there is a link between Combat and the programs developed on the stripped-down version of the TX-0, the first fully transistorized computer, programmed in MIT's computing department in the late 1950s.
Aarseth (2003) writes that aesthetic studies of games may have become possible because videogames "unlike traditional games or sports, consist of non-ephemeral, artistic content (stored words, sounds, and images) which places the games in question much closer to the ideal object of the Humanities, the work of art" (p.1). It is difficult to imagine that the pure representational ability of a cartridge like Combat is any greater than that of a deck of playing cards or an intricately carved chess set. What is different is not the copious content of Combat, but the fact that this game is an interactive computer program. Combat's nature as a "game program" allows new sorts of complex simulation and play, and this is, or should be, the critical factor that enables new sorts of detailed study and analysis of it and of videogames in general.
In closing, here are some questions that hopefully will be more useful to ask of Combat and of other videogames: What other games, game forms and game elements do they draw on? What player skills from other games will transfer to this game? How exactly is the game played, with how many people, doing what sorts of things? Also, what programming language was the game written in, using what sort of development process? How many people were involved in designing and producing it, and what earlier code was directly incorporated or otherwise re-used? How does the game play with or against the platform on which it was implemented and the history of programming on that platform?
There are certainly games with important cinematic connections (Karateka, House of the Dead), dramatic connections (Fa çade) and literary connections (American McGee's Alice, The Hobbit, Varicella). In working to understand these, the related sorts of analysis may be useful. Some of the most interesting games, if they are to be fully understood, will certainly require study from a variety of different disciplinary perspectives. Still, when considering computer and videogames overall, two commonalities stand out: they are all games, and they are all implemented on computers. The first and most essential connections, and the most important forms and contexts to consider, should certainly be those related to gaming �" on and off the computer �" and to computing.
This paper is based on a talk I gave at the conference Form, Culture, and Video Game Criticism at Princeton University on 6 March 2004. Thanks to the Game Studies reviewers for their comments and suggestions.
 The unit came to be known as the "Atari 2600" only after the release of the Atari 5200 in 1982.
 The cartridge was not included with the VCS throughout the entire retail lifetime of the console, but it was made available through other channels, for instance, as a packaged retail cartridge from Atari. The Sears Telegames packaging of the game named it Tank-Plus. Zellers, a Canadian department store, sold copies of Combat called Frontline.
 Platform is represented by one layer in this model of computer games, but platforms are not monolithic. They can consist of layers of hardware and software (standard hardware running one of several possible operating systems, for example), and they can be modular as well as layered. Even standard, sealed consoles such as the Atari VCS have add-on hardware that creates a different platform with different capabilities. An example is seen in the keypad controller that was sold with the Atari VCS Star Raiders, but which could be used with other cartridges.
 The way a game is packaged and distributed (in a cabinet in an arcade, or online, or in a shrinkwrapped box) might also be considered at this level, although these aspects can be varied independently of the programmed interface; these aspects could be treated as part of the context, but are probably better understood as being paratextual. Some of the difficulty in understanding these sorts of elements in this framework comes the way analysis has been divided along formal lines, a division that may not be suitable for all important material aspects of a game. A similar multi-level model of material analysis could, perhaps, be developed to address this.
 Images can be gratuitously included in the interface no matter what, but they can only represent something meaningful to the game if the game form affords something that can be represented in images.
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