If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Mutant Madness is a fighting game where you play the role of an agent that needs to get rid of all mindless zombie-like citizen. Use barehands, guns, chainsaws and other weapons to fight them all. You can earn upgrades and extras by killing the maximum of zombies.
Arrow Keys - Move.
Spacebar / X - Attack.