really fun game - very simple but super effective mechanic, constantly having to balance upgrade / health vs damage. It'd be awesome to know ahead of time what the next wave will be composed of. I really started hating myself for missing my shots as it became more and more risky to do so. I played a good 20 min and I'm still not sure what the best balance is. Curious if all the levels are generated on the fly?
in any case, with a bit of music, this would be a really great game on mobile!