A few uninventive gameplay mechanics, but overall, just as fun as the other great Build engine games.
Gameplay-wise, this game is just as adrenaline-filled, hard and awesome as Duke3d. All the action is fast-paced, and the weapons are inventive, ranging from sticks of dynamite and shotguns, to a staff that steals the souls of your enemies to use as health, and a voodoo doll.
There are a few elements which detract from this otherwise excellent formula however. There are platforming elements in some levels that break up the flow of the action, and are generally annoying. These are less of an annoyance than the boss battles, however. These guys are *hard*. Fortunately however, both of these are pretty easily circumvented, the platforming elements are short, and the boss battles can just be outright skipped.
The thing that sells this game over its contemporaries however, is it's combined horror and humor. The sounds the enemies make are excellent for providing the mood. Cultists call out in strange-sounding dialects, ghosts scream incessantly as they chop you to bits, and severed hands make strange sounds as they move to crush your windpipe.
The game alternates between scary and humorous expertly. One moment you can snicker to yourself, feeling like an almighty god having killed 10 enemies at once, and the next you're frantically shooting at the severed hands as you realize there's no way to get them off once they're on you.
All-in-all, this game is an excellent example of what the mid-90's had to offer FPS's before Half-life came along, and the pure adrenaline rush of fast-paced combat is worth it. Highly recommended.