Complete each achievement to get the allotted gamerscore. If you have an Xbox 360 gamertag, you can log in using this same gamertag and the achievements will count the same as if you were playing the 360 version.
Unlockable How to Unlock Alien Archivist (20) Collected all Alien Captive Recordings Among the Stars (20) Completed "Among the Stars" Not of This World (20) Completed "Not of This World" This Galaxy Ain't Big Enough... (40) Completed "This Galaxy Ain't Big Enough..."
Contributed By: Guard Master.
Know Something We Don't?
You can submit new cheat codes for this game using our Cheat Submission Form.
Have We Been Fooled?
If you see a non-working or fake code in the list above, let us know by using our Problem Submission Form.