Hmmm, bit of mixed feelings on this one. I feel like my initial impression wasn't that great:
While the climbing mechanics were intriguing and I liked the whole 'single player but coop' concept, I felt like the whole 'jump up then the person below jumps and you jump off them mid-jump' was unnecessarily awkward to have to utilize, the rope mechanic was really janky and mashy to deal with, and the game didn't really introduce any significantly new mechanics or level layouts as it went out, just minor differences.
The story also felt super lazy with tons of parts that could've been utilized to flesh out the characters or introduce some subtle hooks or just have some flavor/fun, were instead just replaced with filler like "talking on the way to the mountain" or "shows picture of sister" (why not actually show a picture?) until the game just last-minute dumps the moral on you at the end in a very cliche and almost comical way, like a cheesy after-school special or something. Heart's in the right place and maybe it's a good thing that it's so chill about it instead of being dramatic or whatever, but yeah, it was pretty cheesy.
The game was also lacking some critical elements like a quick restart or anything like that to get out of unwinnable stuck situations. The awkward way the game would squish when you get separated, while funny, was really glitchy and should've probably just caused a restart or something instead. Also what's the point of showing L/R below a character when it just gets lost in the graphics of the ground?
Having said all that, though, I did, for some reason, find myself going back to this to finish the game. Something about wanting to see what happens at the end and actually getting used to and having fun with the climbing controls after the initial awkwardness of it: not sure exactly what. So yeah, something about it hooked me in some way: not nearly as professionally as I think it could've done, but I came back and had some fun, so credit where it's due.