Last Stand
Survive all five waves in the battle for Object Rho ("Arrival" downloadable content)
4/12/2011
1:57:52 AM
Very Rare 5.1%
Covert Action
Rescue Dr. Amanda Kenson without attracting hostile attention ("Arrival" downloadable content)
4/6/2011
3:07:27 AM
Ultra Rare 4.9%
The Ultimate Sacrifice
Complete the Arrival DLC ("Arrival" downloadable content)
4/5/2011
6:49:47 PM
Rare 10.3%
Tactician
Hit 20 different targets with multiple biotic powers to combine the effects
3/24/2011
6:17:43 PM
Very Rare 8.7%