Oh, this was fun, I love a good tower defense and yours had a nice unique feel to it. It was pretty obvious to me what made the big guy spawn, so after my first run failed, the second time I saved up a surplus to get ready and absolutely unload on him. Maybe if he spawned based on a timer, the player would have some harder choices to make whether they want to invest early in economy or defense. Also I loved your choice of music. Nice work, I had fun here :)