Well sir, I understand you are making a lot of updates as I can see, but If you need help with some things, I can definitely help. I don't think pausing between each wave would be that hard if you just keep a variable in the world or something like that keeping track of the changes in waves. And for the pause thing, if you haven't figured it already, theres ways to only detect one touch. I won't detail it unless you want me to. I'd be glad to help you in anything you need

I think this is a very good game and very well made. I understand this is in its alpha stages so just a suggestion, perhaps you should add upgrade options at the beginning of each wave and then make there other options of attack (air strike, whatever else). Just to add some more variety to the game instead of getting to the point where there's so many zombies its impossible to handle

Yes, I'm aware of this. its because there is no 4th level as of yet. I plan to add multiple levels, along with balance(making sure its not too hard or too easy) and more advanced features soon hopefully.