You play the role of a magician, who is called upon by the townspeople to defeat his ancient archrival Nemesis again. After having defeated Nemesis in the past, his minions have erected a huge museleum in his honour, and as a result the townspeople are forced to live under a rule of horror. You must once again venture into the catacombs, defeat Nemesis and free the townspeople.

Catacomb Abyss is a fantasy first-person shooter game. Similarly to the previous game in the series, it casts you as a mage who can fight enemies and destroy whole sections of walls thanks to the use of fireballs. You can find bolts and nukes, which make for more effective weapons but are one-use, healing potions, scrolls with hints, and keys.

However, unlike in Catacomb 3-D, where you spent the whole game inside a dungeon, here you'll explore various environments, both indoors and outdoors. There are new enemies to face, such as zombies that come from under the ground or skeletons that come out of walls.

New to the game is a radar which shows you the location of foes. However, you have to find gems of various colours to use it effectively; each gem allows you to see a specific type of enemy on the radar. There isn't a compass in the game, but various areas of the maps still have specific names.

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