Great Ceaser's Host

LEGIONNAIRE is my latest computer game, a war game manufactured by the Avalon-Hill Game Company. It is a real-time game of tactical combat between Romans and barbarians in the time of Caesar. The player takes the role of Caesar, commanding up to ten Roman legions against a variety of barbarian tribes.

I also wrote a war game called Eastern Front 1941, published by APX, that is strategically more complex, but similar in many respects to Legionnaire. Since ANTIC asked me to write a bit about game design, I thought these two efforts could serve as useful examples.

Eastern Front pits the Nazi Germans against the Russian armies on a realistic map of eastern Europe. The player commands the Germans and controls unit strength, deployment and movement, while the computer controls the Russians. The "map", or playfield, is several times the size of the screen, which serves as a "window" on the map. The player views the remote parts of the map by "scrolling", or moving the joystick so the screen window appears to move across the map.

The design advantage of the big map is to allow much more detail and variation within the playfield, and therefore, more playability. The visual effect of scrolling is handsome as well. The disadvantage is that "action" can be taking place on parts of the map invisible, for the moment, to the player. It can be argued that this realistically simulates the commander's condition and enhances the game, but it causes problems, too, especially when the technique is applied to a game like Legionnaire.

How does Legionnaire differ from Eastern Front?

The biggest difference between the two games is that Legionnaire is a real-time game where Eastern Front is a turn-sequenced game. Thus, you have plenty of time to think over your moves in Eastern Front, but Legionnaire does not give you this luxury. The pace is slow enough to give you some time to plan your move, but not so slow that you can relax. In the heat of the battle, you must be able to rethink your plans very quickly; there is very little time for reflection at the moment of truth. For this reason I think that Legionnaire is a less cognitive game than Eastern Front. I also think that it is a fundamentally more exciting game that Eastern Front. It is not as meaty a game; and war gamers may feel that it doesn't have enough strategic subtlety.

The basic game system is much the same as Eastern Front. There's the scrolling map with terrain, and you give orders to units in much the same way. Movement and combat follow a roughly similar pattern.

With Legionnaire, however, the scale of the playfield is much smaller. Instead of thousands of square miles of territory, we have perhaps a hundred. The terrain has variously pitched hills, and the pitch affects movement of player and foe. There are forests, impenetrable to both sides. Each START places all forces in new locations, so each battle is tactically unique.

As Caesar, the player gives "orders", using the joystick, that cause the legions to move specifically and separately in complex attack patterns. In a well- played game of Legionnaire, Caesar's units will be moving simultaneously in real time to close battle with an enemy similarly moving.

The graphics of Legionnaire are slightly better. Units are displayed more imaginatively. There's a little more color. I also added some animation to show which units are moving where during the turn. It is safe to say that Legionnaire goes beyond Eastern Front in its use of the technical capabilities of the ATARI computer.

Why a game on Romans and barbarians?

Simple. This is a real-time game requiring "art)ficial intelligence" on the part of the computer. It's tough enough to design algorithms that produce intelligent play, as in Eastern Front. Designing algorithms that run so quickly that they don't noticeably slow down a real-time game is really tough. Thus, the algorithms for Legionnaire must necessarily be pretty stupid. Stupid algorithms imply stupid opponents. In all of military history, how many situations arose in which one opponent was generally recognized to be pretty stupid? Not just wrong- headed, misinformed, gutless, or foolhardy, but deeply and genuinely dumb? Not many. Romans and barbarians was the closest approximation I could find. Even this scenario isn't quite fair to the barbarians, but fortunately, few barbarians buy software.

That question is hard to answer. The very first version of Legionnaire was written in eight weeks around March 1979, on a Commodore PET. The game was fun but it didn't seem to hit the nail on the head. I sold fewer than a hundred copies. Rob Zdybel of Atari saw the game, liked it, and put together a simplified version for the ATARI 800. This was subsequently released by APX as the game Centurion. Subsequently, I joined Atari and attempted to interest the company in war games, but to no avail. So, in June, 1980, I signed a contract with Avalon-Hill giving them the rights to Tanktics and Legionnaire.

By September, 1981, I had finished work on Eastern Pront and was casting about for a new project. AvalonHill had been impressed with Eastern Front and wanted something like it, so I promised that I would get to work on an adaptation of Legionnaire for them. I spent three months solving some of the fundamental problems with the game, then began serious programming work in January of 1982. I delivered the game to AvalonHill in late February. Polishing required three more months. The final version was delivered in June of 1982.

What were the hardest parts of the effort?

Undoubtedly the most difficult part of the effort was reconciling scrolling with the real-time nature of the game. With an oversized, scrolling map, it is quite possible for the player to be looking at the wrong sector when some crucial event happens elsewhere. Since Legionnaire is a realtime game, it is impossible to stop the game at intervals to allow the player to peruse the map. I solved this problem with a variety of schemes.

First, I kept the overall unit count low to reduce the chances that the player would have units scattered all over the map. Second, I added sounds. A marching sound tells the player that some unit is marching, and a very distinctive combat sound warns him of a battle somewhere on the map. Third, I designed the combat system to encourage the player to keep his units bunched together where they could all be seen at once. As units march, their fighting strength wanes, and when combat is joined, unit strength falls due to death and injury. Holding high ground is an advantage. These features make it desirable for Caesar to keep his legions together, march them as little as possible, and hold the high ground.

I think I was successful; but this problem, which kept me awake at night during the design phase, is rarely mentioned by people who play the game.

Another big problem arose from the real-time nature of the game. The player's input is processed during the Vertical Blank Interrupt, while the units are moved during the mainline execution. With Eastern Front it was quite possible to keep the two processes separated so that they would never interfere with each other, but with Legionnaire it was far more difficult. For example, what if the main line routine wants to move a unit that the player has picked up and is holding? Does it rudely jerk the unit out of the player's hands and move it, or does it politely wait, hanging-up the game while the yokel stares at his< unit? I eventually devised a scheme that resolved the dilemma, but it cost me several tufts of hair.

What was the easiest part of the effort?

Working with the Atari MacroAssembler, a magnificent piece of software. I programmed Eastern Front with the Atari Assembler Editor cartridge. Those who have read the source code of Eastern Front can testify to its clumsiness. By contrast, working with the Macro-Assembler was a real joy. I only wish that I had had Jim Dunion's DDT debugger then. The combination of the MacroAssembler, DDT, a RAMDISK, and a good printer makes Assembly Language development a very smooth process.

If I had it to do over again, what would I change?

Very little. I find that the game plays smoothly and well. I wish I could have added some better sounds_those marching feet do get tiresome after a while. I have a vague feeling that Legionnaire doesn't have the staying power Eastern Front has, but I can't put my finger on the problem. It could be that Legionnaire, with only ten Roman units maximum, just can't match the sweep and scale of Eastern Front. I don't know.

Will it sell?

I think so. The biggest marketing problem with the original Eastern Front is that it is too cerebral, too strategic in nature. Those not used to war games have difficulty adjusting to the APX version. Legionnaire does not have this problem. It is much easier for a beginner to understand, and much more exciting to play than Eastern Front. But there's no way to be sure. Only time and the customers will tell.