This game has the same feeling as Ruins of Machi Itcza and NONDECIVER, which definitely is a good thing; I loved both of those games very much when I played those. The length, along with the difficulty, are just perfect. It's really rewarding (and also stressful) to do the no lantern run section. I personally love the glitchy feel of the dark green rooms, and the seemingly repeating ones that are slightly off. The sound and music are both really nice (nice shoutout to Goldeen and Cubone(?)). The movement was nice, you have a good control over your jumps, although it sometimes feels like the character walks a little too slowly.
There are, however, some points that were less good. Basically every element of RNG was very frustrating; the jellyfish were slightly annoying, but the boss fight was horrendous. I really liked the boss music, the atmosphere, and the way to defeat it (even the screen shake didn't feel bad), but the fact that its movements are random and you sometimes just have to wait for more than a minute just to make it go away from a specific torch, along with the fact that its attacks sometimes are inescapable, feels unfair. Also, I don't know if it was intentional or not, but its hitbox felt random as well. Sometimes I could walk through his legs, and sometimes the horns didn't kill me, but other times I only need to touch one pixel to die.
Another point is chapter 5. It felt very strange, completely different from the rest of the game, which is a shame. The movement was just guessing, which felt off for a game where the focus is skill. And the empty rooms with just the white squares was a nice challenge, but also did not feel like it belonged in this game. (Another small point is that I was very surprised that there WAS a chapter 5, as the boss fight really feels like the end of the game.)
Overall, I still really like this game, and I'm very impressed with the design and overall atmosphere. It's exactly my kind of game, and if the boss fight was more balanced, I would definitely give it a 5.
Keep up the good work, and I can't wait to see when you come out with another game, if you ever decide to make more.