Update! Added a link to play in full screen for Madness Interactive! Sometimes it can be hard to control when the flash boundaries are there.

This is my favorite flash game of all time. Once you get used to the controls and a feel for moving the mouse around, this game is highly addictive and fun. You are basically a weird little cartoon guy, and you go through a matrix-like arena killing everyone. There is a wide variety of weapons and different characters. Another fortunate part about this game is there there is also a practice mode, challenge mode, and cheats. The cheats are as follows (enable by going into the options):

Willis- invincibility
NewYorkMinute- Infinite bullet-time
Guide- Aiming line
Armstrong- 2x Reach
FLCL- Infinite ammo
Hop-: Higher jump
Arnold- 4x strength