I am become DEATH! 26089 DPS
I enjoyed this! I could see myself firing it up and playing for some waves. It's kinda nice because yeah you have to monitor some upgrades but it just fires by itself. I totally broke the game just getting gold and weapon upgrades, as you can see...
Like urbantides commented, the lack of audio really holds it back.
One quick pointer since you are in Godot - when you make the game full screen now it does not actually scale properly. You will need to go to Project Settings > General then scroll to Display > Window. Under Stretch, change mode to Viewport, and the game should scale properly when set to full screen. It's one of the first things I do in any game I start to make sure it works.
Have a good day!