This is an expansion you will need the base game Nemesis to play."You already know how it feels to be chewed by an Intruder? Do you know the feeling of what it's like to run from a Night Stalker through a Mars base? Do you want to know what it's like to be ripped to pieces by a gruesome Carnomorph? You are in the right place. This is a new Alien race with its own mechanics, new nightmare fuel monster miniatures, and a totally new experience. Compatible with Classic Nemesis, Aftermath and Lockdown."