Wow, I really appreciate the in depth write up! This is a lot of great feedback and some awesome insight. It will be hugely helpful in future projects. Reflecting on the jump, I am starting to think it's more of a level design issue than a character controller issue. Like the jump is deliberately clunky, and while I do think the values could be tweaked to feel a lot better, I don't think the levels were adequately designed to be explored by a clunky character. Those tedious jumps at the start are a key example of that, it's just a design decision that would fit better with a lighter character controller that could carelessly jump up them without thinking much of it. So I think if I were to revisit this project, that would be something I would have to keep in mind. I would need to be sure to design the levels in a way that fits the character better.
I'm really glad that people seem to like the dash jump, the speed you can build up by timing the jumps was a really fun unintended effect that I just had to keep. I would usually just hold shift then tap space as soon as the dash animation started to get a chain going, but yeah the timing can be tight. In a revisit of this, I would lean more into the dash and utilize it better given people's positive response to it.
I appreciate the praise on the puzzles, I did end up pretty happy with how they tested all your abilities in interesting ways. Its really hard to know if people are going to understand what the problem they're meant to be solving even is so conveying all that without being condescending or annoying is a really delicate balance.
As for where you got stuck, it sounds like you didn't get the vertical boost power up, which you get at the end of the third level, the alien spaceship. I have noticed some people miss this levels existence, so I think it could have been signposted better, but yeah there is a third level where you get the final powerups and play with a new mechanic.
I do wish I could have made the cave level more cave like, I originally had plans to sculpt it out to make it feel more natural but time restraints made me fall back on just making it with normal primitive shapes, I'm glad to hear it still worked for you though. The scale of everything was not something I initially planned but it was something I fell into over time and ended up liking a lot, especially with how quick you ended up being with the dash.
I'll be happy to see your recording! And I really appreciate you not only taking the time to play it, but to write this great review. Thanks so much!