Here's how you play:
Controls:
a)Movement:
-Forward: W
-Backward: S
-Left: A
-Right: D
Weapon:
-Switch to Rilfe: Press 1
-To pistol: Press 2
--To use the weapon, scroll up fully and you will see a crosshair.
-Then,
-Fire: Left click
-Reload: R (Remember to used up all your ammo first before reload)
-----To switch to other weapon, scroll down fully to disarm and press the 1 or 2.
-Run: Q (Hold it with W,A,S,D)
-Secret:- Lurk around the second level and you'll discover the boss level!
Good luck!