In Mass Effect 3 for the PC, PS3, and Xbox 360, you can unlock a special armor and weapon set called the Reckoner Knight Armor, and the Chakram Launcher.
To unlock these in Mass Effect 3, you just need to download and play the Kingdom of Amalur: Reckoning demo.
The Reckoner Knight Armor boosts close quarters combat, and increases some weapon powers as well.
The Chakram Launcher is essentially an explosive disc launcher.
