Mass Effect 3’s new multiplayer DLC Retaliation adds in some new environments, the Collectors as enemies, and some more unlockable kits. There are also some additional weapon upgrades. Some of the levels now have “Hazard” version, where there are dangerous environmental factors like sandstorms and lightning.
“Retaliation” is also introduced. It is a multiplayer mode that checks co-op performance and can offer “Challenge Points” which can be used to customize the player profile. The amount of points earned is dependent on your experience.
Retaliation will be available from Playstation Network, Xbox Live, and can be downloaded for the PC.