Kind of fun to see we had a similar idea! It's sort of hard to criticize it in an unbiased way, but there are some cool elements I wanted to point out.
I like the different maps! They all manage to feel pretty unique, and I'm particularly fond of how the Hard Map has enemies that come from "behind" the default camera position- it makes it so the camera is more than just a quality of life feature. Very cool!
I also like the concept of the shop system. In practice the limited options means you tend to receive duplicate options, but I like it in concept, it's not something I've seen done in a tower defense game before