Thanks a lot for taking the time to write this out, I appreciate the feedback a lot. About the jump height, it is possible to jump higher by holding in the jump button, but it is very possible that it's still not high enough. Either way, it is on me for either not making the controls tight enough and/or not communicating to the player that there is a mechanic for getting longer airtime.
I definitely should have let some other people playtest it before the deadline, since many complaints about the game turned out to be physics-related(Hard jumps, not enough friction between the player and ground/platforms, etc.).
I will have to post the game to a different page I believe, since updating it directly is against the rules of the Gamejam it was part of. I had some ideas for how I could improve the gameplay, but I figured it was a waste of time, and I'd be better off dropping it, but reading your comment really inspired me to finetune it, so thank you for that.
I'll be replying to you some time in the coming days once I have an updated version of the game, if you're still interested in playing it :)