Fun game! I found the concept of climbing around with your arms both very amusing and also very intuitive and interesting to come to grips with, if you'll pardon the pun. Felt good to get better and more efficient at moving around, and I loved pulling down the keygates as it felt so satisfying. I haven't beaten it yet but I definitely plan to come back since it was quite fun, though I'll admit that part of me is a little reticent because the game, as fun as it was, sometimes felt a little frustrating and slow to play at times: nothing major, but sometimes it just felt a little wonky to have to climb everywhere bit-by-bit, and annoying to get your hands past certain obstacles.
One part that was a bit confusing was the fact that I wasn't ever sure how far I could move my arms at first: sometimes it felt like they could reach very far, and then other times they couldn't, and that's because I didn't realize I was crossing them over (reaching to the right with my left arm). Perhaps the game could actually have the graphics of the arms overlap in front of the face so it was more apparent that's what was happening, or be more forgiving to allow it.
EDIT: Have now beaten it and had a blast! I appreciate the bonus hard paths that taunt you: always love an optional challenge, haha.