Adventures in Nimnul's Castle is an action game were the player must guide the chipmunk characters Chip and Dale through nine levels while avoiding enemies and obstacles. Each level takes place in one of three locations: outside the castle, on the castle steps, and inside the castle proper, with the stage objectives varying between them, such as simply avoiding all enemies while moving across the screen or collecting items such as screws. The player is awarded points for each successful objective they complete, and has three attempts to make it through the game. Short cutscenes appear at the beginning and end of the game, as well as after certain levels

The Rescue Rangers having to rescue their partner Monterey Jack, who is caught in a mousetrap in Professor Norton Nimnul's castle. To accomplish this, the chipmunks must infiltrate the mad scientist's abode while avoiding his mechanical guard dogs to collect parts so their friend Gadget can build a flying machine to reach him.