Save humanity throughout the galaxy from certain annihilation

Gain the loyalty of the mercenary ("Cerberus Pack" downloadable content)

Build three houses

Gain the loyalty of the Professor

Win an online vs. match with all rule sets.

Visit 100% of the planets in an unexplored cluster

Had a conversation with a cactus.

Conquer Stage 9.

Fully upgrade one weapon category.

Purchase all skills in one category.

Revive a teammate in a multiplayer match.

Dry a cop out.