ME3: Stop a Cerberus kidnapping.

ME3: Bring a veteran officer aboard.

ME3: Chase down an assassin.

ME3: Return to active duty.

ME2: Save humanity throughout the galaxy from certain annihilation

ME2: Use the Omega 4 Relay

ME2: Obtain geth technology

ME2: Gain the loyalty of the quarian

Kill 2,000 enemies in Mass Effect 1, 2 or 3

ME2: Confront the Shadow Broker

ME2: Gain the loyalty of the Cerberus Officer

ME2: Thresher Maw defeated

ME2: Gain the loyalty of the thief