Make contact with the Ethereal hive mind.

Build the Gollop Chamber.

Successfully assault an Overseer UFO.

Build the Hyperwave Relay.

Acquire 1000 credits in one month.

Kill an alien while flying. Single player only.

Kill 50 aliens with explosive weapons.

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

Kill 150 aliens.

Gain access to the lowest level in your base.

Advance one of your soldiers to Colonel rank.

Build a Workshop.