Thank you! :)
Yes, I'm planning to work on it more, and I want an Android port as well, but I have another smaller project to finish before that.
Well maybe it's just me but I found the dragging more comfortable, you don't need to press anything to switch. Just tap or hold anywhere on the screen anytime you want.
And, yeah the zombies are very dumb, because they are only moving to the player's direction in a straight line, if they are closer than 480 pixel, no AI involved at all. I'm planning to add a field of vision, and A* pathfinding, but for me it's not something that I can implement in a couple of hours... :D