Thank you for your kind words! I had big issues with motivation on this project, since the slower and more deliberate style of control just wasn't really my kind of thing, in addition to spending a week being sick. So, I'm really happy that some people had fun with it.
A few things I had originally planned didn't make it into the gamejam version, such as: a second boss, story cutscenes, and visible effects of upgrades on the monster's body. I might try to submit an updated version to Super MVM that will be closer to my original vision.
For the time being, I used the grace period to push a few minor updates, including some additional audio and visual feedback, as well as an ability to reset the save by holding R!