I'm impressed with what you got with this little time.
You should definitely keep developing this game, make interface more readable - tower fire rate, damage etc., immediately on screen.
Crafting in TD game is something new, should be more accessible in this game, cause every player would just build the towers with the parts from chest, and place it without thinking on his own.
At first just fix the bug with drag'n'drop and sounds playing after losing. :D
Really big potential to make something bigger, really cool concept.