I got the idea of it, but I think you need to change something about the implementation. Just let players click a button instead of having to type in the commands. You have to do that mid-battle, as the zombies never stop, which makes it frustrating. There's not much explanation of the commands and no stats, so you can't see any strategic aspect there. I would have had waves of enemies with pauses where you could set up traps, barriers, and automatic defences. Check out Plants vs Zombies.
Having the player control a character was a positive, that some people miss when making auto battlers.