The movement feels snappy and responsive. This was really fun to move around in. Landing on those narrow beams never felt janky, and when I missed, it felt like my fault, not the controls. I also like how falling wasn't overly punishing. You clearly thought about how players would mess up and made sure it didn't turn into a slog to climb back up to where they were, keeping the pace of the game up.
Visually it has that retro vibe while being clean and readable. And it runs super smooth on WebGL which is super important to a platformer like tihs. This was a simple concept done really well. I enjoyed the climb.