This was a very well made submission. The physics feel really fun to control, and the jelly-cube had some very satisfying movement (especially accompanied with the sounds). The graphics are really stunning, and I'm surprised you managed to create all that in the time allotted. You had a very well integrated tutorial too. The grappling mechanic, though a common take on the theme, is very well polished here and it was very fun to grapple onto things.
A little note on the grappling though, I found the controls a little bit difficult to use. I think it would be much better if you aimed with your mouse, it's what I'm used to and I think that the WASD keys should be reserved for the jelly's movement. The propulsion was a cool mechanic, though I did get a bit confused on how to use it first, as when I used it I just saw some sort of bullet on the ground; you kind of need to spam it in order to create momentum to propel. It would be nicer for the propulsion to immediately propel the jelly.
I really liked this submission, it's extremely well polished. I would love to see you expand on this one post-jam!