You will kill grunts till 100 and defeat the sheriff to be free
The kill count will count down by failing to continuously killing the grunts

If the Hourglass counter drops to 0 you loss the game

Killing 6 grunts in 3s you will gain 5's in the Hourglass
 

Controls

Movement:
Up: W
Down: S
Left: A
Right: D

Weapon:
Shoot: Left mouse button
Switch: Mouse Scroll Up