Get 50 kills with non-fleshy weapons.

Kill an enemy with an enemy's arm.

Regenerate with Splatter Siphon.

Kill 6 enemies within one second.

Keep your team alive through the suicide mission

Complete Mass Effect 2 twice, or complete it once with a character imported from Mass Effect 1

Use the Omega 4 Relay

Hack a geth collective

Gain the loyalty of the quarian

Hit 20 different targets with multiple biotic powers to combine the effects

Thresher Maw defeated

Gain the loyalty of the Professor

Gain the loyalty of Archangel