Complete all instances of Guardian Angel.

Complete 1 challenge in any level.

Build the Gollop Chamber.

Earn the "Excellent" rating in every performance category on a terror mission.

Kill an alien while flying. Single player only.

Acquire 1000 credits in one month.

Successfully assault an Overseer UFO.

Get satellite coverage over every country on one continent.

Advance one of your soldiers to Colonel rank.

Recover the Hyperwave Beacon.

Build a Workshop.

Stun an Outsider.