What worked:
The visuals work really well and give a creative and unique look to this game. The feeling when the light finally runs out of stuns is pure bliss. I now know how final bosses feel when I keep foiling their plans.
What didn't:
If I don't keep the light in my field of view, there's a good chance I'll take the wrong dead end and have to go all the way back up, losing the light. This is fine as a lose condition innately, but how I got there ends up being making one mistake, then losing to "pick-a-door" when I get to a fork. This part doesn't feel very good. Maybe add a trail to the light? Also giving the boss some skill based abilities to help could be a fun idea, especially if you plan on expanding the idea. This way there's some counter-play (unless I missed something) to being stunned repeatedly or taking the wrong path.
Bugs:
Didn't see any.
Great job!