Hi its me Keksi. My english is not that great but I will try to give you the best feedback I can do.
First of all, I really like it. I really like the artstyle and how the game feels.
I quickly found out the best way to get through the waves is by deleting every turret after each round and place new ones with the colour I need to defense in this round. That gives it a pretty high difficulty mostly because you can't stop between the waves and prepare. A stop button or key would be really helpful I think.
I don't have to say that much beside the difficulty. Most things who miss in the game right now you know already. Tutorial, more tracks, menu etc. So far I really enjoy the game and look forward to new updates :)
My Discord if you need more feedback or else. I have too much time while the virus is around lol. Keksi#4669