Rid the subterranean catacombs of as many demonic bad guys as possible. Watch out for lava pits, acid, and (of course) the bad guys. Collect power-ups and money along the way. Between levels, you can purchase upgrades to your health, speed, armor, and weapons.

Use arrow keys to move around the playing field; mouse button to aim and shoot. Numbers 1-5 to switch weapons, or press Shift to cycle through weapons. Press space bar to bring up options/map screen.