ME2: Gain the loyalty of the Assassin

ME2: Complete the investigation of a derelict alien vessel

ME2: Gain the loyalty of the Professor

ME2: Thresher Maw defeated

ME2: Disrupt the shields of 25 enemies

ME2: Successfully recruit the Assassin

ME2: Defend a human colony from attack

ME2: Hit 20 different targets with multiple biotic powers to combine the effects

Kill 250 enemies in Mass Effect 1, 2 or 3

ME2: Successfully recruit the krogan

ME2: Unlock 15 new Mass Effect 2 codex entries

ME2: Complete a mission discovered by scanning an unexplored world