The game consists of one screen which depicts Robbie's garage that he has converted to be horticulturally friendly apart from the numerous holes in the wall through which various creatures make their entrance. Shelves lining the walls are where he keeps his cans of nerve gas handy. Robbie must run around the garage floor and intercept each intruder as it homes in on his plant in the center of the screen, being careful not to make contact as one touch from an invading creature will instantly vaporise Robbie into a cloud of monochrome pixels.