Happy to see a tower defense game. One of my favorite genres but doesn't always get the love and support it deserves.
The game was really hard at the start. It takes a while to understand what each tower does and I'm still not sure I fully understand what the best strategy would have been (I made it to wave 4). The UI could use some work, they're very small but there's a lot of room on screen for them to be bigger. The It would also be great if you explained what each tower did when the user clicked on it (like Bloons TD 5/6). I like that the enemies shoot at your towers, that was a fun addition.
Fun game overall!