Hi there, cool game!
I'm a big fan of the grapple, though I feel like gravity might be a tad too strong, sometimes making it hard to align your hookshots properly. Not sure if there was none or I just stopped playing too soon, but there didn't seem to be any powerups, which is unfortunate, I think a dash/double jump and such could've been fun in combination with a grapple.
There's not a lot of art in this, but the bits of art that it did have were totally fine! Music felt a bit unfitting perhaps, but sound effects were pretty much on point.
Game's clearly unfinished, but if you expand on the whole grapple platformer bit and just polish a bunch, it could be a really awesome experience!