Borderlands 1 and 2
Dishonored
Aliens vs Predator series
CoD 1 and 1.5 -United Offensive
BF 1942
L4D 1 and 2
Doom 3
BioShock 2
Red Orchestra 2
Quake 2, 4 Arena
Unreal Tournament (all of them)
Mech Warrior 2,3, + (except Mech Commander)
Serious Sam 1, 1.5, and 3
Portal 2 (guns - no killing per say)
Half Life 2
FEAR series
Killing Floor
Dead Space 1 and 2 (OTS)
I know I am missing plenty.