Decent design. Now you have to improve the game. Add more stuff like moving glass or rings to pass througt or any kind of bonus.
Put a challenge : first level score at least 400 points, then 600 then...
Great idea ! Not so difficult after 2 tries. Too much time before the wave comes at high level, and it's hard to repair a tower where there is a defence.
I'm not sure, but it seems the last upgrade in rapid tower is too expensive. 4/5
Ok. 2/5 today. I will update when you will. I think ennemy should get harder quickly : I've played for a dozen waves and win with only 6 blue towers. Need some boss too.