I played for a few rounds and am not really sure what's going on. Hitting everything perfectly keeps the ziplinee straight which allows to hit stuff more easily. Missing once causes a fun downwards spiral of chaos.
I'm unsure if it's possible to get back to the straight zipline when you play perfectly for a while (because i didn't manage to play perfectly with a roller coaster zipline :D)
The music, sfx, sprites and animations are great. I like the aestethics. Would have been cool of the level moved left instead of the zipline, but it works the way you have it currently.
Overall you did a good job. The fun bits were very fun and it is also challenging.