I am a sucker for grappling hook games and this is no different. Super fun demo, but number one change I would make immediately is the camera zoom. i could hardly ever see the jump I was trying to make with the next swing.
Its somewhat unclear how fast you need to be going for some high jumps and the spike level's beach ball to flag without swinging jump you make at the end of several difficult swings was to tightly spaced for me to see it was possible so I ended my playthrough there.
The animation done for the player sprite was impressive among the games I've played this jam. Squash and stretch, you got that down
My one major gripe is that the music doesn't fit and became annoying after a while and some sound effects for the player would do miles for the game feel.
I am very interested in grapple physics and if I ever get to work on a long term project I will be doing something with a grapple and momentum.
Great work!