Dang, I missed few...
Really fun! A super good amount of content too with a pretty good difficulty curve. Some of the lengthier sections could have used more checkpoints but it wasn't that bad really.
The biggest level design flaw in my opinion was near the end the branching path where you're punished by having to backtrack and repeat the whole thing if you choose wrong. Not fun. Guess which path I chose first...
I kept hating the design choice of that random wave for pretty much the whole play time. Especially on that flappy bird challenge room. It just felt mean to have a "random" thing come mess up your game every now and then in an already very tight flying section. And other times you could kinda abuse it to reach higher spots and so on but it being on a pretty lengthy delay made it that you'd have to wait around for it. And just waiting is never really that fun. But then seeing the final boss, it kinda made it worth it. Don't really like the wave as a design choice but tying it in to the story made it excusable and yeah, that was the theme.
Also didn't really like how you needed to backtrack from the challenge rooms. I kept thinking I should try not grabbing the checkpoint in the end there to just death teleport back but never got around to actually try it. I think it would make more sense it the run backwards was also a challenge with some additional hurdles but often it was just the same but a lot easier. Only the flappy bird room was the only challenging bit but even that without the need to collect the runes wasn't that bad.
On that same challenge room, the controls became a bit of an issue too. Quite often you had to dip very low to not hit the spikes when jumping up but being so low, you kidna didn't have enough mouse room to properly be beneath the character. I guess there was room though but being in the midst of action, there wasn't quite enough time to focus on pixel precise mouse cursor placement.
Good looking pixel art! There were few times it got a bit confusing to figure out what is an actual platform and what is background. I think you even used some of the same assets for both. At least the orangeish pipe was sometimes walkable and other times just on background.
The spike and enemy hitboxes felt a bit too punishing. Would feel a lot better to be able to graze the spikes and survive. It's one of those things that just makes it feel better when the scales are tipped a bit on behalf of the player. That way when you get hit and fail, you know for sure it was on you and not the game just being unfair.
And then it's the opposite for collecting the runes. Felt like you could even go through them sometimes and only the very center of the player spite did the collection. Like in this section I managed to not get the rune but hitting the spikes right under it three times before actually succeeding.
Anyways, good job, fun game! 👍