Hey there! Thank you for your feedback, it's really valuable. I'll go point by point:
Some levels have basically what amounts to a forced death on the first time doing where you have to stop your momentum and switch direction
Yeah, I designed them that way in order to force the player to use the recoil mechanic. I think it's still ok to have that kind of sections sometimes, but I'll restrict them to only the beginning of levels so they don't feel unfair. Besides, using the recoil is usually the best way to go fast, so if they want to get more stars they'll end up using it anyways.
I think there's a bug with the Vines mechanic, it seems like they all share the same cooldown or something
I just tested it and it doesn't happen to me... The way vines work (this is not explained in any way in the game) is that if you hold jump you automatically grab them at the best moment in order not to lose speed. So if you're going towards a circle and tap jump, nothing will happen. Maybe it was that? In any case, I'm happy with the way vines work but we do need to teach it better to the player.
Dustforce has checkpoints that make the level essentially not count for scoring if you use them
I've thought about adding a practice mode for each level but only after you beat it... For the first time playing it's in our plans to add a way to look around a level (like a free camera system).
The game made me slightly motion sick which is something that literally never happened to me in any game before
This is very important to me. I could try adding an option to remove backgrounds. Can I send you a version without backgrounds so we can test if that helps?
Thanks again for taking the time to write feedback, it's all useful. And I'm glad you enjoyed the game!