Thanks for the ideas/feedback!
Regarding point 3: in the early game, the railgun has high projectile speed, and it's good to have freezer towers that slow down enemies. In the late game, you need to build the most expensive towers and place everything strategically — then it becomes manageable. I wanted it to be a bit of a challenge for the player.
As for point 5 – I’ve already added that to the game. And yes, it's just a small hobby project. I've been working on it for a few days.