Cool concept! I agree with everyone else that there should be some tutorial explaining what to do. I think the control are a bit inconveniant too but once I got the hang of things it was pretty fun!

Some kind of simple in game tutorial would be nice next, took a while do figure it out! :b

It took me a minute to understand what was happening, but I think this could be a great tower defense game, nice work!

I definitely need a tutorial here, it's also unclear if I should press the button and if it's successful? if there were some sounds for this, it would be much clearer,

good concept, you just need a tutorial to explain the features better.