The Siege Game mode Add-on for Resident Evil 6 (Xbox 360) has 5 achievements worth 125 gamerscore.
Defeat 100 player-controlled agents and 100 player-controlled creatures.
Defeat the BSAA 100 times.
Defeat the BSAA as a creature without dying once.
Win 10 times.
Protect the BSAA without any of them getting hurt.