The player takes the role of an unnamed soldier sent into a portal to stop an enemy, code-named "Quake". The government has been experimenting with teleportation technology, and created a working prototype called a "Slipgate". Unfortunately, a portal to an unknown dimension has been opened, and death squads begin to emerge, killing and robbing as much as they can before returning through the gate. Once sent through the portal, the player's main objective is to survive and locate the exit which will take him to the next level.The game consists of around 28 separate "levels" or "maps", grouped into 4 episodes. Each episode represents individual dimensions that the player can access through magical portals (as opposed to the technological Slipgate) that are discovered over the course of the game. At the start of each episode, the player is deployed in a futuristic military base and he has to find a slipgate that will take him to the alternate realm. The various realms consist of a number of gothic, medieval, as well as "fire and brimstone"-style caves and dungeons with a recurring theme of hellish and satanic imagery reminiscent of Doom. The latter is inspired by several dark fantasy influences, notably that of H. P. Lovecraft; most notably, the end game boss is named Shub-Niggurath and the end boss of the first episode is named Chthon, although there is little resemblance between the game's portrayal and the original literary description.