The main activity of the game was to write a computer program that would operate a (simulated) robot. The player could then select multiple robots who would do battle in an arena until only one was left standing. The robots did not have direct knowledge of the location or velocity of any of the other robots; they could only use radar pulses to deduce distance, and perhaps use clever programming techniques to deduce velocity. No physical dexterity was required or even relevant in RobotWar; there was no way for the player to actually take part in the battle.
The robots' language was similar to BASIC. There were 34 registers that could be used as variables or for the robots' I/O functions. An example program from the game manual follows:
SCAN AIM + 5 TO AIM ; MOVE GUN AIM TO RADAR ; SEND RADAR PULSE LOOP IF RADAR < 0 GOSUB FIRE ; TEST RADAR GOTO SCAN FIRE 0 - RADAR TO SHOT ; FIRE THE GUN ENDSUBThe robot with this program would stand still and sweep its radar in a circle, firing off radar pulses, and when it detected another robot in this way, would fire a projectile, set to explode at the correct distance as estimated by the radar pulse.
In a way, RobotWar was a multiplayer game, in that different people could program their robots, then copy all the robots' source code to the same floppy disk and load all the robots to fight in the arena.
The game was sold in cassette tape and floppy disk versions.