Fun game! I love the GB visuals, the music goes hard, and the grapple mechanic is pretty neat!
The precision/timing requirements are a bit too high for me (though I'm sure some people like that kinda thing) so it could be nice to have a more forgiving mode (bigger hitboxes), slightly more floaty character, etc.
It could also be neat to have spikes or something instead of just a hole for the gaps because it would give the player a chance to avoid death if they parry fast enough (maybe this exists in later levels).
Like others mentioned, it would've been nice to play it in the browser but that's an easy fix! Overall great work!