Killerbot is based on an old BASIC gamed from the 1970's called Escape, where one lead their enemies (who always take a path straight towards you) to blow themselves up on mines, without landing on one yourself. This was a turn based game; each move the player made was responded to by a move by each of the enemies, and then it waited for the player again.
Killerbot, written by Aardvark founder Rodger Olsen, expands on this concept in a couple of ways. Using joystick controls, the game is now in real time where the computer does not wait for the player to move. There is now a mission other than just survival - the player has to traverse the screen from their start point on the left to the cave entrance on the right (to disarm a bomb) . There are two main skill levels - Regular, where your opponents move 1 square for every 2 the player moves, and Master, where they equal the players speed. There is also a guardian robot at the cave entrance; in Regular it only moves vertically, and in Master it can move horizontally as well. This special robot ALWAYS regenerates if you manage to kill it. The skill level specifies how many extra robots are added besides the cave guard, from 0 to 9. You also have the option of allowing them to regenerate as well, or once they are dead they stay dead. Not a bad little game in BASIC for 4K Coco's.
Of note is that Rodger had released this game earlier in late 1979 for the OSI (Ohio Scientific Instruments) Challenger home computers, which were the first system that Aardvark did programs for. I should also note that some ads say it works with either joysticks or keyboard controls; I think that is only for the original OSI versions. The Coco version seems to require a joystick.
Title: Killerbot
Author: Rodger Olsen
Publisher: Aardvark-80
Released: February 1982 (written 1981)
Requires: Color Computer 1,2,3, 4K RAM, joystick, tape or disk.