From the manual: "In this one-player game, you are a sharp-shooting cowboy - the last defense against the hordes of alien Slymoids. Use your Slymoid Scanner and Laser Fireball Weapon to locate and destroy these strange life forms. The devious Slymoids also appear in two other forms - Jelloids and Spores. Chase the Slymoids through fields, castles, and caves. But beware! The crafty Slymoids have turned spiders, bats, and even rocks against you,"