Oh gosh yeah, just like Noon said, super interesting and I think their suggestions are on point!

I like the idea and you have a great start. But as Noon said, the game needs a better balance and there have to be more options how to act. Switchable towers was what I thought, too. Keep on hacking!

Actually quite interesting. If I may suggest, you can play with turning towers on and off, helps push the agenda of letting some enemies leak. I feel like the system needs some rebalancing between the prices and how much health you can 'spend'. Actually, it would be interesting for a tower defense where you literally pay with your own health in the first place. Maybe offer lifegain if you beat a round perfectly?

Sorry for the huge suggestions, its really interesting! I love the start screen and I love what you were going for. Great game!

I don't understand how to win. You need to take damage to earn money, but you always run out of lives. I can kind of see it as a puzzle game, but right now it doesn't seem you can win a single level.

I like the idea you have to let some enemies through to get either lives or money, but the current system is pretty messy and the UI makes hard to see the track while waiting for the yellow balls to go through. 

Also adding tutorial would be great.