Cool game! My brother and I played together... ( 7 and 20 years old respectively ). We really enjoy the music and art style. The first 75% of the climb was pretty easy for both of us. We didn't make use of the "rope" mechanic until it started getting challenging during the final bit of the game ( where it got very vertical) . I would suggest trying to layer the "rope" mechanic with other mechanics to create dynamic gameplay! Maybe "slidy" dark ice? Maybe a bouncy trampoline or something? I could definitely see this game being expanded upon and eventually produced into a full title!
Thanks!