This is really awesome! Love seeing the 3D capabilities of Godot for web-based games on display, I also like the idea of juggling between repairing parts and knowing when to replace them. It would be cool to see the different parts have more of a visual effect (like the laser cannon vs missile). Great work!
A good start, I like that there are multiple enemy tower types. The player goblin frequently gets stuck on the terrain. Also, the camera jumping around each time you switch goblin makes it easy to lose track of which direction you are meant to go - some level details like arrows would make it easier to follow
