Wow, solid little puzzler you got here! Felt very well constructed all-around: movement felt very juicy, well-animated and smooth, puzzle elements felt very intuitive and varied, and the general presentation and world had a cool sense of mystique to it. With such good gamefeel and fun brain-scratcher puzzles that kept escalating, as well as that bit of an intriguing story hook and cool atmosphere, it was very simple for me to get addicted and blast through this!
While character movement was generally smooth and well-animated, there were definitely some oddities. The character physics were a bit wacky at times, with the jump feeling both very floaty on initial jump and very heavy on falling, and in general the little guy felt a bit too fast which made some puzzles, such as the fan puzzles, a bit tricky to be precise in your movements. The walljump/cling interaction was particularly terrible as well with how the little guy just floats a few feet away from the wall, awkwardly leaning in mid-air in the opposite direction: you'd think at the very least he'd lean into the wall and make contact with it for the sliding to make any sense!
While I did like the puzzles a lot, I will admit that the difficulty curve was a bit wild due to some real crazy spikes here and there. One of the earlier spikes for me was where you need to put a mirror box on top of a box and then resummon the box to drop the mirror box: stumped me for quite some time as I don't think any puzzle before that set any sort of precedent for any of those new techniques of stacking boxes or resummoning as a trigger or whatever to serve as a hint to work from. I didn't mind the spikes so much as they did spice things up and I was surprised at how much some puzzles pushed outside-the-box thinking and wanted more of that, but outside of those instances, things were pretty easy, so it was a weird mixture of severe ups and downs.
There were a couple of other weird things, like there was a moving platform where if you stand on it, you're fine, but if you stand on a box on the moving platform, you won't follow it and instead fall off, and I also found the lasers a bit fiddly and annoying with how too precise they were due to them bouncing at the exact spot of contact instead of just generalizing towards the center of the block for consistency. But overall I had a great time and got all the way to the end: cheers for this!