The game is inspired by first-person shooters such as Quake, Doom and Serious Sam, with the emphasis on killing large numbers of monsters. The game is divided into five chapters, each about five levels long. The player's objective is to get through each level, from start to finish, by slaughtering hundreds of monsters. Fighting monsters often occurs in mass battles, where the player has to fight an attack by a swarm of enemies in a large room, while the exits shut and heavy metal music plays in the background, and after such a battle, the player passes a "checkpoint" which advances the game, the exits open up again, and the music returns to the usual softer tune played in the level. One of the game's most important aspects is its diversity, with each level presenting a new location with various themes and graphic styles. The levels include castles, monasteries, an opera house, graveyards, and more. Monsters are also very different, with new ones almost every level. There are five "boss" levels where the player fights a boss.
The game presents an option to complete a special task each level, which results in the player getting a "tarot card", a rare, hard-to-obtain bonus. Each equipped card provides different bonuses for a small amount of time (30 seconds), like powered-up weapons or slow motion.
The game also features a multiplayer component. It includes classic modes like Deathmatch and Capture-the-Flag.
