Overall a good entry! I had fun playing it.
The soundtrack is really good, I especially like the change from Building to Defending Phase!
The art is nice, the little animations the robots do, e.g. the mining thing, is a nice touch.
Two points of criticism: the repairing is extremely finicky and I don't like the pause between waves with the full screen info, where I have to press the button to continue. Something like the switch between phases to keep the gameplay fluent would be better.
I also noticed, that you changed the default Godot web export to show the Mech Jam Logo. Nice! :D