The character controller felt very very stiff. I also did not understand the grappling mechanic properly. I thought I could swing it out at any point and if I hit a crystal, grapple myself up or swing. I think the character controller absolutely needs to be less heavy and stiff, the grapple would feel more natural if you have a limited range and only could grapple to the specific objects. If you have played Teeworlds, that is a really good example of a game that uses a grappling hook very well, perhaps you could use this as an inspiration, as well for the character controller. I think this is what holds it back the most. I struggled so much to get up the vertical section, it was really difficult to the point I died there multiple times.
I appreciated the handdrawn animation and the spritework, it was really cute but you gotta improve the gameplay feel. I assume you have not done many games yet, which is totally fine, but especially in gamejams, people mostly look at the gameplay first and foremost (sadly). If it doesnt click, its hard to reel them in and keep em playing the game. I hope this feedback can maybe help you out with improving things. Those are just my 2 cents and what came into my head when playing this game.
Also besides that you have a scam comment on your itch page, be careful about that.