Like the initial tower-growth concept - I believe there is much potential depth to it.
Feel like the variety of towers was a little bit unnecesarry. Not like the game doesn't need them at all - afterall it's the stamp of the genre to have different towers to pick from - but I just wish that the growth mechanic would be properly explored first. It would be cool to have 1-2 more creative growth uses implemented in the game and only after that I would love to see what other towers can do. This way the game would feel more focused on its main idea.
Beyond the mechanics I simply enjoyed a nice pace of waves comming in. Also the shooting sound, visuals and damage felt pretty satisfying making the game fun and cozy to play.
Good job!