Thank you for such detailed feedback. I'm so happy you stuck with our semi-functional game!
Both Sarah and I completely agree with all of the issues you bring up. At some point in the jam we realized that we couldn't figure out how to make the yo-yo any better and had to work with what we had. This jam has been such a great learning experience for us and all of the feedback we have received makes us want to work harder and learn more. We could make the yo-yo disappear and have a little animation of them putting it in their pocket and taking it out. Also, seeing that GIF of the string bending with the terrain makes me excited to learn how to do that so thank you for the suggestion.
An important part of a GameJam is knowing when to start cutting, and what to cut. I think if you had prioritized anything else than what you did, the game probably would've suffered as a result - so I think you made the right calls. You made something really great given the time constriants, and with a bit more time I know you guys could make it even more awesome.