There's also Zombietown: Paint It Red. Edit: Almost forgot a unique one, Adventure of Guns N' Zombies.
Honestly, Zombieville and Inkvaders are the best of the bunch - you're better off just sticking with those
try red rage, it went free yesterday. i didnt like it much since im bored of sidescrollers but you might like it.
... which isn't much like Zombieville at all, except in visual style. But you should still check it out
