Demons have invaded and overtaken the Union Aerospace Corporation's Mars Research Facility. Carnage and agonizing death blanket the station as misery permeates the air. As one of the lucky few occupants of the station to have escaped unscathed, your shell-shocked psyche struggles to cope with the horrifying images you have seen. Things won't get better any time soon, but it falls upon you to battle your way through the demonic horde and lay this evil to rest once and for all.