While presented in a side-scroller format, Crazy Castle differs from standard side-scrollers such as Super Mario Bros. in that Bugs Bunny does not have the ability to jump; therefore, only by taking different routes can Bugs avoid enemies. Some of the levels have boxing gloves, invincibility potions, safes, crates, flower pots, or ten thousand-pound weights that can be used against the enemies in the game. As a result, the game has a "puzzle-solving" atmosphere.
Players score 100 points for every carrot with the last one in each floor giving the player an extra life, 100 points for every enemy defeated using invincibility bottles, 500 points per enemy using boxing glove, and 1000 points per enemy that gets hit with heavy objects. Because most NES game cartridges lacked the ability to save, passwords can be used to start at a certain level in this game.