Ultimate Doom-gog Link

: Upon reaching Deimos, you discover the moon has been pulled into Hell itself.

You are a space marine, the toughest of your kind, sent to the research facilities on Mars’ moons, Phobos and Deimos, as a disciplinary transfer after assaulting a superior officer who ordered you to fire on civilians. The UAC had been experimenting with inter-dimensional travel, but the gateway collapsed, allowing the literal legions of Hell to swarm into our reality. The Survival Mission Ultimate Doom-GOG

: You must fight through the Phobos base to find the gate to Deimos. : Upon reaching Deimos, you discover the moon

As the demons invaded, your entire unit was wiped out in minutes, leaving you as the sole survivor. : Upon reaching Deimos