You are Mappy, intrepid mouse cop on the trail of a gang of cat burglars. Naturally you, as a mouse, are no match for the cats so you must stay out of their way, Pac-Man style.
The only way you can get up to the higher levels of the mansion is by bouncing off trampolines - but these have limited uses. Too much bouncing and they break, propelling you down to your doom. Doors situated at key points in each level allow you to stun cats (oddly referred to as the Mewkies) and get by.
Challenging and inventive, this is surprisingly addictive, but probably for retro enthusiasts only.