Worm Whomper plays like a hybrid of Missile Command and Centipede. Players maneuver a horizontally shooting spray gun at wave after wave of hungry worms, snails, slugs, bugs and other swarming creatures that are attacking Felton Pinkerton's crop of golden sweet corn.
Shots of poison, which are unlimited in supply, affect only the first pest in their path. However, players are also equipped with three plough balls capable of destroying every enemy in its path. Players earn three extra plough balls each time a wave of pests is eliminated.
If a pest touches the spray gun then both will dissolve, but luckily, unlimited supplies of guns are in a tool shed positioned at the bottom of the screen. If a pest (other than a moth, which lays eggs that become inchworms) touches a corn plant, the corn will shrink, wither and die. With every four waves of pests destroyed, a new corn plant will spring to life (up to ten onscreen at once).