That was a really good tower defense game. The graphics are beautiful and it was really satisfying destroying all the little monsters.
I understand you did it for the limitation, but not being able to reset the colors of your guns somehow was a bit annoying. Unless I'm missing something?
I was also expecting the game to end at some point, but I guess it just keeps going. I gave up after round 51. If this was a full game with more levels and enemies I would enjoy playing more of it.
Nice work!