It's been said already, this game is NOT worth enormous amount of money that it goes for, but this game does hold a rare distinction, along with Little Samson, in being a /great/ rare game. It's a cute 'em up with great characters and interesting, unique options for your ship- I mean, broom.
Emulate it, play it on Turbo Everdrive, or get a repro.
Your prototypical dungeon crawler (it's in the name). As a single player game, it's been done better in games like Gauntlet and pretty much all dungeon crawlers that came after. However, as a multiplayer experience, it's a fun outing that gives you a blank canvas in which to have a mini D&D session.
First of all, you gotta get a working paddle controller. Once you do, grab a friend. Play on nothing less than the highest difficulty.
Your goal is to diffuse the cheery bombs the Mad Bomber at the top of the screen throws at you. You have three tiny, tiny buckets of water to put out the fuse. Each time you miss a bomb, you lose a bucket. The more bombs you catch, the faster the bomber gets. And once you get past about 600 points, the Mad Bomber goes berserk and starts throwing the bombs faster than even Sonic the Hedgehog could probably catch them. Once you lose all three buckets, KABOOM! All the bombs detonate. See how many you and a friend can get, and see who can get more.