Silent But Deadly Achievement
Silent But Deadly15
Stealth kill 10 Enemies with the Striker Crossbow
One of the coolest weapons in the game obviously needed its own achievement! The best mission to unlock this one is during the "Hijacked Well" mission (which also nets you an achievement). Not much skills to it, just aim, shoot and kill 10 enemies unaware of your presence to get this achievement. You can get this in co-op mode as well. THIS ACHIEVEMENT IS ACCUMULATIVE!