I love the idea! Outside of it just being balanced to be a little rough though, I think it would also be more satisfying for the player if kills feel like they award way more than the cost for killing them even if you compensate with having the towers cost more. Right now, it never feels particularly rewarding as a player imo. 

The idea is great ! but after a few try you realize that you need to grind a lot to just be able to go to level 2 with enough gold to make a tower, probably you did not have enough time for balancing the pace and difficulty. Love the idea that even shooting costs money, like those memes with the money cost of missiles, turrets and so on we see online haha. Maybe you can try to add more variety in terms of tower, capital cost, shooting cost and so on so we have more choices to make.

Hey, your game is cool and the concept is realy great ! Just i have an little issue i'm spawning with $0 on level 2🥲