Hey, LibGDX! That's what I work in. Not for this jam, I only did music, but for a bigger game I'm trying to make. Slow going but I like having so much control. Would be nice if it had any hope of being finished, though...
Your game's a really good premise. I like that there's a time and place to have many weak guys as opposed to the big ultimate dude. I agree that the music added a ton, and I liked how you switched between the two synced tracks, but a crossfade over a half second or so would make it smoother. I don't know if this is the best way, but you can have each track playing, one muted one not, and modify their volumes multiplied by the delta time in the render() method when it's time to crossfade. I think.
I also loved the death animations/sound effect. Super cute for some reason.
At the end of the day, though, it just wasn't super fun...? I wish I had better feedback, but I don't really know why, I typically love turn-based strategy.