How To Unlock: Kill 1,000 zombies barehanded.
While playing through the game, use your jumpkick to kill zombies. While leveling up, you'll receive additional barehanded moves. Not only are these moves fun to mess around with, they'll make killing zombies quite a bit easier. There is a magazine located in "Ragazines" inside the Royal Flush Casino. The magazine is called Hand-to-Hand. Use this to help you with your kills. The kill count is spread across all playthroughs, given you restart the story from a previous save, but there have been reports of it not unlocking, so it's best to contain them in one playthrough, just to be on the safe side. Note: The moves you receive while levelling are random. Don't worry if a certain skill hasn't unlocked yet, you'll get them all eventually.