The implementation of the theme can be stretch but the game is actually insanely fun.
Very simple controls and premise that is extremely easy to get into. The gameplay loop is very simple, reminiscent of mobile-game design but the mix-up with the green guys is a great way to introduce variety and keep things interesting.
I find myself always constantly having to remind myself about which keys to press for which attack, maybe consider adding some UI for which button to press on which area?
Otherwise, really fun small game actually!