Cool game idea and I like how you implemented the grappling hook mechanic but there are a few things to look out for, I listed them below:

• there is no dead zone underneath the stages despite the small level design
  • you can add a plane and make it a few times bigger than the base area. Reduce the alpha in color so that it is invisible and then, you can add in code so that when the player touches the plane, it can reuse the rest script
• if you fall far enough, you will clip through the ground because the reset doesn't reset velocity
  • you can implement a change to make the rest button also SetPlayerVelocity = 0; or something along those lines
• the second stage is impossible to beat currently mainly because the rocks needed to reach the grapple are too high up for the player to reach
  • if you move the first rock down even a bit, it should fix this
• BIGGEST GRIEVANCE: THE MUSIC 
  • it is loud and when playing with headphones

if you fix at least the music, me happy :)