Nice and simple. I enjoyed the explosion at the end!
I was a bit confused about what the far shadows on objects were intended to convey - they just seem to float in mid air rather than feeling like they're cast on a surface. They don't communicate anything meaningful in terms of vertical placement, and a shadow on the floor or ceiling would communicate a lot more about where they are along the forward axis.
Hope you had a positive experience using Godot, and thanks for doing a Linux build!