As a drop-in upgrade for Pac-Man, Crazy Otto brought many changes to the game, although basic gameplay remained the same. Most notable is the main character (Crazy Otto) had legs and blue eyes. The monsters also have feet, as well as animated antennae. Other changes included new mazes, music, sound effects, and bonus fruit. Otto and his female counterpart were featured in 3 new intermissions, the last of which shows the arrival of baby Crazy Otto, Junior.