2 things I love: When the training (namely strength) lines up with the song I'm listening to, and getting 514 combo on defense. One Finger Death Punch and Undertale don't have anything on me!
I, and others here, would love to see a sequel. Perhaps there could be more modes, like a gateway you can try to power with elementals? And more stuff (units, towers, etc.) in general. Really fun game!
You're right, it was a bug. I just updated it twice in a row trying to fix bugs with switching the enemy :P. Hopefully it works now.