The lack of any kind of game feel(particles, screenshake, flashing sprites), no sound, and the fact that your little mining pet gets in the way when fighting made this one rather rough to play. Also, when you don't hold down the jump, it feels extremely unsatisfying. I like the concept, art style and the little mining pet is a neat idea, but as you mentioned, the lack of time to develop seems to have killed this game.
Viewing post in Mysterious Mineshafts jam comments
I'm really sorry for all of the issues, polish was something I was putting off until further into the project and I ended up dropping development around halfway through the jam. Platformers aren't something I've had too much experience with yet so the code for holding down jump is a bit jank and because I didn't have as much time as I would've liked it was something that wasn't able to be fine tuned.