Instructions
Punch twice as fast as normal by pressing the "Melee" button and the "Weapon Switch" button alternately at a rapid pace. Your character will punch quickly and kill the zombies.
Get the Assault Rifle, and ensure it has a full reload clip. Hold the "Left" trigger, and press "Y" and "Y." Then hold down the "Right Trigger" for 10 seconds while still holding the "Melee" button. After 10 seconds, let go of the "Melee Trigger." This will unleash the Super Shot, which can take out a tank easily as well as hordes of zombies.
Perform a Hot Swap in the game by picking up a different weapon than the one you currently have, then re-select the weapon you want. This will reset your weapon to its original, or cherry, state. This can be useful in situations where you are low on ammo or are facing a large group of zombies.