Good entry to your first game jam! I agree with the other comment about the acceleration and deceleration - it was challenging to control the character when I was sliding around. I felt that I had to either keep going and jumping without stopping to keep the momentum, or risk not having enough to clear a jump.
I had the same issue with not getting things past a prototype stage. I felt that each individual part had to be perfect before I could move onto the next. But after a while I realized that in order to actually make whatever I was working on get better, I had to get many different projects under my belt. Once I realized that it was easy for me to walk away from half finished or broken work so I could learn more by starting and trying to complete more projects.
Best of luck in your game dev journey!