Not that bad at all. This is a game that Apogee released between Wolfenstein 3D and Rise of the Triad. Basically it uses the Wolfenstien engine with some modifications, the best of which is a map so you're not lost throughout the entire game. It also adds a greater variety of enemies, money which can be used to buy things, switches which change the level, and so on. It isn't quite as memorable as Wolf3D (mostly because it lacks the freshness of that game) but if you like the older 3D games like Wolf3D or Catacomb Abyss you might want to try it out.