Great visuals and sound! I liked the feeling of it a lot. But it seems the guns can also shoot through walls if the player is close enough. And I think it might be better, if the camera is a little bit more zoomed out, as the reach of the guns can hit coworkers, that are out of the camera. Especially the last level suffers from this, as it get hard to tell what's going on.
Oh, and I didn't know you can actually aim in this game. Have to press LM and moving the mouse instead of just moving the mouse seems a little conter-intuitive.