Honestly probably the best game I've played from this jam so far (of about 20, but still). I really liked the tower defense idea, since it's a genre of game that I wouldn't think would work with only one tower at all (at least more than trivially), but you made it work, and fully thought out the idea. The gems keep the player engaged too, so they're not just waiting while the tower does its thing. I'm super impressed too that you managed to have a boss stage as well. And of course the art is really good.