What worked:
This is a really cool concept. I like the risk vs reward of taking it slow and knowing what's going on versus gaining a higher score by keeping track of everything mentally. It feels good to play mechanically with everything feeling responsive.
What didn't:
The difficulty curve may be a bit sharp. If this was expanded you might want to make level packs and have the difficulty be more gradual.
Wall jumping feels odd while in the dark. I don't think there's any way to fix this (maybe particles when wall jumping?).
Bugs:
Didn't find any.
Great job! (00 32'31'', 6 deaths)