Things I liked:
In your development video, you made it clear that your main priority was the polish and graphics. You certainly succeeded there-- it's incredibly rare to find a game jam that feels as finished as this one. The character is super likable, the stretch/squash animations did exactly what you hoped, and I was just as enthralled by the death animation as you were. Your concept was simple but easy to understand, and communicated clearly through the first two levels-- I know you were concerned about making your game easily accessible to a new player, and it shows in your game. Even the menu felt great, which is unheard of for game jams.
Potential areas for improvement:
The quality of life issues you and others have mentioned weren't that big of a deal to me. However, you mentioned that you have trouble designing levels for puzzle games, and that's something that I felt like was definitely noticeable. Most of the levels felt very linear, with a simple, clear path from beginning to end, and even then I was able to complete almost all of them with pieces to spare. I think you were hurt by trying to make the game more complex initially-- it's probably more obvious in hindsight, but I think by splitting your attention to thinking about the speed boost and changing toolkit, you weren't able to really hone in on the consequences created by your simpler set of elements. The last level, where you had to jump into a box on a platform, was brilliant and I would have loved to see more of it; maybe bouncing a box on a spring, maybe removing a platform while the robot is on it, maybe bouncing the robot over a wall of spikes to bounce off a clear patch of wall.
Overall:
This game works perfectly in every area you set out to succeed in-- it's gorgeous, with an extremely cute robot, and very accessible and enjoyable for anyone. Even my critiques on level design could be easily due to personal preference; the other comments seem to like the simplicity of the levels, and it definitely helps fit your criteria of being fun for everyone. Well done!