I just finished it in one sitting. I thought it was great. More games should be small, intensely focused on their fun mechanics like this. It just layers and layers and layers onto its incredibly satisfying and fun movement system and then, once it basically runs out of ideas for using that system, it ends. It was right about 4 hours for me to complete it like 95% or something. I think I missed 1 collectible I'm sure about and maybe 1 or 2 other things, but I was pretty thorough.

Can't recommend it enough. I might learn to speedrun it, it's that fun.

Edit: If anyone here doesn't know what it is, essentially it's a parkour puzzle game. As in, the puzzles are mostly "how do i parkour over there with the tools i currently have?" it has combat, technically, but the combat is used extremely sparingly. enemies are rare and bosses are, uh ... well there's 2 of them.