Great job on some of these tight platformer mechanics! The climbing mechanic felt the best and most responsive for me; it was an interesting twist on the one-way platform cliche seen in a lot of platformer games. I think the grapple mechanic has a really nice start, and in my opinion I feel like it'd be more rewarding if the player had more control over the trajectory, like choosing between directions with the WASD keys, or maybe pressing left and right to aim. Maybe if the platforms were much larger, and they were easier to target with the grapple, the player might feel more compelled to swing around and experiment, but the current aim-and-wait mechanic and the tiny platforms don't allow for the fun moves I expect to be able to do with such a mechanic. Also I'm not sure if this was intended, but I like the way you could actually float by holding down jump when you fall off a platform without jumping. I think this could be pivoted to be a base mechanic where you glide down instead of falling when pressing space, and it might allow for more deliberate movements/reactivity in the air.
I honestly haven't seen too many grapple mechanics in platformers that felt appealing to me, but combined with the climbing and tight controls I think there's a nice start to a cool grapple mechanic and great platformer game here. Congrats on the submission!
P.S. I could cheese my way to the end of the game by flying into the wall while spamming the grapple :P