A very cute well rounded game that deserves more attention in the jam, I loved this a lot, best thing Celeste ever taught me was the Pico8.
I also made it to the bug level Spike and Balls as others reported
Viewing post in Dungeon of the Red Mist jam comments
Yeah. I do have a fix ready to release as soon as the jam ends which fixes the bug by replacing the gate, adding a button where one should had been, and adding a sign making fun of the bug and giving a bit of lore reason why the bug happened.
After testing, that thankfully seems to be the only level which had a bug like that, so the good news is that the post-jam version should be completable up to Level 00.