I just played this game again.
hahahahhahaha. Oh this is great.
This is very very old...my first game I actually completed.
The Wild West has been taken over by an evil corporation called Fun Hats, led by Fou Puffin. Your Job- kill all cowboys controlled by Fun Hats, and Fou Puffin. Press Left and Right to move, space to jump, aim with your mouse, fire with left click, and press control to swap weapons.
Music Credits : Timesplitters 2 and Naruto