to easy!!!!!!!! one very hard beat it with 100 life left

no upgrades is a big nono

Pretty cool, I like the effects you used for smoke and things like that. Hot-keys would make it easier to navigate through the different windows, though...and maybe it's not necessary to have the waves wait for so long.

It was okay, but nothing really different from any of the other tower defense games I'd seen.

Just another tower defense game, nothing that hasn't been seen before. The difficulty setting doesn't seem to affect much at all, and the fact that the difficulty of waves is sporadic means the initial difficulty setting is trivial.
It was playable though, but not complicated or interesting enough to keep me invested.