Brutal game, but pretty fun tbh, with a few minor frustrating things. Here's just a few specific notes:
One of the most precise inputs is delegated to left shift which uses the pinky finger. My poor pinky was not built for this much precision platforming!
I think giving the player a bit of bonus upward velocity when using the bomb jump would make it feel better and more intuitive to use.
Stuff like having like a split moment where the player pauses before being pulled by the grappling hook, or having the grappling hook still pull for a bit more after the wall its attached to phases out might help with game feel and make timings a bit more forgiving for some of the tricks.
I have a pet peeve against spikes being lethal from the sides, and especially from the back. If it's not important to the gameplay, I think changing the way they work would be a nice QoL change. If it is, maybe they should be aesthetically replaced with another hazard.
I got to the volcano level and stopped, but I'd really like to try again soon. Really nice entry!