There is an official add-on to the game with three additional levels and new enemy types, available as a free download on the developer's website. Dismemberment is one of the game's key features, which allows limbs to be shot off enemies. On this mission, there are many locales including military bases in the present to tombs in ancient Egypt. A soldier is on a mission is to stop mutant beings invading Earth from different timelines. Chasm: The Rift is a first-person shooter for the PC developed by Action Forms, and published in 1997 by WizardWorks, GT Interactive, and MegaMedia.