O.R.O.S.I.

O.R.O.S.I.
1 Freeware available for O.R.O.S.I., see below

Background story:

O.R.O.S.I. Inc. has been assigned with a special task to develop a lethal weapon you cannot shoot. Sounds impossible? Not for scientists from O.R.O.S.I! Still not convinced? Then enter the training simulator they developed specifically for you and experience it yourself!

Controls:
W, A, S, D - move
Shift - sprint
LMB - "Shoot"
RMB - Change gun screens between showing the player's health and the number of remaining enemies.