This one gave me a headache and ALMOST busted my controller.
Just a fare tip on the Final Showdown, which I did on my first try with this. Do the basic two controles; use a rubber band or anything on your 1st (Swift Blade warp) and kill with the 2nd. If your #2 dies, then just pause the game, unravel #1 and kill two zombies. Your 2nd will be revived. Pause again; ravel #1 and continue, till the Horseman (After 5 Freaks). Keep #1 warping and don't worry about #2 dying, because the Horseman will end up killing the zombies, which automatically revives #2. Now just keep shooting the Horseman (2nd stage) with the MG, it effects him when he tries to warp on you.
Watch the vid on the Horseman's 2nd stage. The video starts off with round 2 of baddies. All credit goes to zlLiQUiDlz.
I hope this helps :]