Doofus is like a reverse Sleepwalker - you play a simpleton (hence the title) and must get through a series of platform levels ensuring that neither you nor your pet dog get hurt. The game unusually scrolls from right to left, with the dog simply following you. The platforms are often on different levels, providing multiple routes through the game. Most hazards in the game can be shot, but others can be avoided by jumping. A number of bonus weapons and other enhancements are on offer.