Wow this is probably the best I've seen here. Brings back memories of hitman II...
But please prevent the crosshair from being white on white - that's mean ^^ and from a professional merc POV there is no white sight / crosshair. Maybe a black one with a red dot, but I've never seen a white one.
2 little things: F1 key not working on laptop that has the F-keys in context of a FN key. And please add arrow keys parallel to WASD, or optional (but not via F1 key ^^)
Anyway, excellent !!!