Cool idea, I spent more time on your game than I was planning to :D
I think the difficulty peaked somewhere around Wave 20. All my turrets were overpowered later and I was just grinding points, but the first waves were fun to play.
The music doesn't loop! (Neither does it in my Defold game, so I guess the "Looping" flag just doesn't work and needs to be overridden when playing the sound...)
