Amazing, truely amazing ! I really liked the art and the sound effects/music fits really well in the game.
But, because I really liked the concept, I will give a few things that frustrated me while playing :
What I like about tower defense is to watch my army of towers destroy waves of ennemies. But during the game, you can’t just sit and watch, you have to upgrade and upgrade, without looking at the core game. So maybe, it could be fun to stop the process of playing for the last wave? The player would just be able to watch his towers doing the job! :)
Again, it’s a very good game, especially in only 3 days. Good job mate