Really nice tower defense, it was so hard to keep up with all the enemies sawarming the field at once.It was a bit hard at first to balance between the different colored tiles. A problem that I noticed is that the more progress you make troughout the waves, the less you're incited to use regular tiles, since they are not fast enough to eliminate enough enemies to survive the next wave. Maybe increase their original speed a little, otherwise that's pretty much it. Also, if you lose a battle, return to the main menu and retry, the game won't spawn enemies anymore. Apart from that, nice job :)