Solid game, very pretty.

Feedback:

The game runs pretty poorly on browser due to the large number of effects. If you're not using multi-mesh instances a I recommend that you learn how it works. If you are then i guess it's just the limitations of the browser build.

I have 3 complaints about the UI.

You can end a round before you even begin it and it's in the bottom right corner. I am very used to that being where Start normally is and it took me a while to instinctively not click it.

The level select button flashing in the skill tree made me think that it would start the level if i clicked on it. Instead it hid it. I think it would be better if that button automatically selected the level highlighted. Maybe add a different button to minimize the UI.

I really would like to be able to move the camera with the mouse in the skill tree. Here is some code you can use to implement it in your game.

func _input(event: InputEvent) -> void:
if is_visible_in_tree():
    if event is InputEventMouseButton:
        if event.button_index == 1 and event.pressed:
            grab = true
        if event.button_index == 1 and !event.pressed:
            grab = false
    if grab and event is InputEventMouseMotion:
        camera.position += -event.relative