Eastern Front (computer game)

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Eastern Front (1941)
Developer(s)	Chris Crawford
Publisher(s)	APX, Atari
Designer(s)	Chris Crawford
Platform(s)	Atari 8-bit
Release date	1981, 1982
Genre(s)	Strategy
Mode(s)	Single player
Rating(s)	N/A
Media	Cassette, floppy disk, cartridge
System requirements	Atari 8-bit computer, cassette recorder or disk drive
Input methods	Joystick

Eastern Front (1941) is a computer game for the Atari 8-bit series created by Chris Crawford in 1981. Recreating the German invasion of Russia during World War II, Eastern Front covers the historical area of operations during the 1941-1942 period. The player commands German units at the corps level and must contend with the computer-control Russians, as well as terrain, weather, supplies and even unit morale and fatigue. It is widely considered to be one of the first computer wargames that could compete with paper-and-pencil games in terms of depth of play.^[1] According to Crawford, it is the first wargame to feature a smooth-scrolling map.^[2]

Contents 1 Gameplay 2 AI 3 Development and Versions 4 References 5 External links 5.1 General information and resources

[edit] Gameplay

Unless otherwise noted, this description is adapted from the original game manual, available here

Eastern Front puts the user in control of the Germans, in white, while the computer plays the Russians, in red. Units are represented as boxes for armored corps or cavalry, and crosses for infantry, an attempt to replicate conventional military symbols given the low resolution. The screen shows only a small portion of the entire map at one time, smooth-scrolling around it when the joystick-controlled cursor reaches the edges of the screen. The map covers the area from just north of Leningrad at the top to Sevastopol at the bottom, and from Warsaw on the left to just east of Stalingrad on the right. The terrain is varied, including flatland, forests, mountains, rivers and swamps, each with their own effects on movement. Cities are also displayed, and are a major source of "victory points", the player's score.

Most user input is via the joystick, which is used in place of a mouse in selecting units and entering orders. The game is modal, switching between an order entry mode and a combat mode. During order entry the joystick can be used to select unit and enter movement order by pushing the stick in the four cardinal directions. Up to eight orders can be entered for any unit, the units attempt to move as far as possible in any given turn. One annoyance is that adding new orders required the user to watch an animation showing existing ones, which is slow.

After entering orders, the combat phase is started by pressing the Start function key. The screen shows combat by flashing the "attacked" unit, which might be forced to retreat, or be destroyed outright. When all possible movement and combat is exhausted, the game returns to the order-entry phase. The number of grid squares moved during one turn was limited by the terrain the units moved over. Each turn represents one week in-game time, and the game ends on 29 March 1942, after 41 turns.

The game engine included a number of features that dramatically increased "depth" compared to other wargames of the era. This includes muster and combat strengths, which simulated losses due to combat, as well as reinforcements that would slowly increase a unit back to muster strength over time. Supply lines are also simulated, and surrounding the enemy to cut off their supplies was an important strategy for the human player, who faces an overwhelming enemy numerical superiority. The game also includes the concept of "area of influence" which allows front lines to be constructed without requiring contiguous lines of units.

The most obvious effect in terms of gameplay was the changing of the seasons, with the rivers and land freezing from the north down. Winter and spring weather dramatically reduces mobility and supply levels, at which point the game becomes purely defensive for the German side. If the player can survive the winter, the arrival of spring offers a renewed offensive capability, but only for a short period before the game ends.

[edit] AI

The computer AI calculated its moves during the period between vertical blank interrupts (VBI). The rest of the game, what the user saw, was run during the VBI period of a few hundred cycles. According to Crawford in Chris Crawford on Game Design, the system started with a basic "plan" and then applied any available cycles to trying variations on that plan, selecting higher-valued outcomes. A few thousand cycles were available between each VBI, so given a typical order-entry phase of a minute, the computer had millions of cycles to spend on refining its plan.

The AI was based on three basic measures of the game state; the strategic situation which attempted to take and hold cities, the tactical situation which attempted to block player movements, and the overall arrangement of the front line.^[3] The AI would first attempt to build a continuous front line in an attempt to prevent encirclements, and would then send additional units on intercept courses to block player movements, and finally any remaining units to undefended strategic areas.

Although the AI was not particularly strong, it made up for this with numbers. Against a player "playing fair" the computer could put up a credible defence. Direct fights were hopeless, as newly arriving units would eventually overwhelm the German forces. Crawford spent considerable time "tuning" the arrival of new units to balance the gameplay^[4] In typical games, the player would attempt to break eastward, and encircle the ever-growing block of Russian units. The Russians were short of the highly mobile armored units, at least early in the game, so it was possible to outmaneuver them and cut off their supplies, drawn from the far right edge of the screen.

Unfortunately, there were ways to "game" the AI. One was to break the German forces into two blocks, and then advance them on alternate turns. The tactical part of the AI would attempt to intercept these movements, sending its mobile forces first one way, then the other, never actually making contact. Another strategy was to keep flanking forces behind a spearhead, which the AI would attempt to block. This would result in the computer forces clumping up in front of the Germans, allowing the wings to move in once motion was difficult.

One "bug" in the game engine was later exploited by players. Since the AI calculated its moves while the user entered their orders, reducing the amount of time the user took to plan their own moves reduced the quality of the computer response. This could be reduced to zero by simply pressing the Start key repeatedly, at which point neither the player or the computer would do anything. This way combat during the winter could be avoided entirely, allowing the player to break out the next spring with full-strength units.

[edit] Development and Versions

Crawford, who worked at Atari at the time, developed Eastern Front during his own time for nine months. In a 1987 interview, he estimated he had worked a total of 800 hours on the Eastern Front.^[5]

Crawford approached Atari about selling the game, but the company felt that wargames would not sell on the 8-bits.^[6] Instead he turned to the Atari Program Exchange (APX), a mail-order operation that distributed 3rd party applications. Eastern Front became an APX best-seller, selling over 60,000 copies. The manager of APX joked that Eastern Front let them keep the lights on. Crawford also released the source code to the game on APX, at a higher price. He later expressed his surprise that while sales of the source code did seem to be strong, no 3^rd-party games were ever released that were based on it.^[7] This code is now available on the internet, allowing it to be examined, although only within the Atari Assembler Editor, perhaps in an emulator.

The game was so successful that Atari asked Crawford to do a conversion to cartridge. Crawford took the time to make a new version, improving many aspects of the game. To improve the gameplay he revamped the AI code, and eliminated the ability to "fast forward" the game and avoid combat. Five "difficulty levels" were added, the "learner" mode with a single German unit in order to teach the user how to use the controls, and each level above that adding more units up to "advanced", which was identical to the original game. In the highest level, "expert", air force corps (Fliegercorp) were added, and the units could be placed in one of several "modes"; normal, assault, defend and move. In "expert" the user could also choose to start in either 1941 with the standard opening, or 1942, with fully developed lines deep within Russia. The new version also added the ability to save and restore games, and added city names to the in-game map (which were previously visible only in the manual). The conversion from APX to official Atari product was fairly rare, although Caverns of Mars and Dandy underwent similar conversions for the same reasons.

Crawford would go on to use many of the ideas pioneered in Eastern Front to produce Legionnaire for Avalon Hill in 1982. Legionnaire used the same map engine to simulate the Roman legions fighting the barbarians, but modified the engine to actually move units in real-time. This made the game much more difficult to "out think" than Eastern Front, as the human user was forced to find the enemy units on the map, plan strategy, and move their units at the same time.

[edit] References

[edit] External links

[edit] General information and resources

• atariarchives.com; Eastern Front by Chris Crawford - APX Cat. No. 20050
• atariarchives.com; source code for Eastern Front - APX Cat. No. 20095
• atarimania.com; Atari Eastern Front (1941) information and scans (APX package).
• Atari Age; Eastern Front (1941), Atari - RX8039.
• Eastern Front at MobyGames
• Analog Vol. 5 No. 22; review of Eastern Front by Jerry White.