Thanks for your feedback! I am definitely planning to change those things you mention, but ran out of time before the submission deadlline.
I'm kind of glad you had a "metroidvania" experience by accident due to the powerup and unreachable coins being in odd spots! I threw in the powerup right before I submitted the level since it was pretty much finished & it wouldn't even be close to a metroidvania without at least one powerup. There's also a couple impossible jumps in the starting room, but I didn't get around to putting coins or anything to make you want to go there. Plus one is covered by the heads-up display! Another thing I need to fix.
Some of those hard jumps might just need level design solutions instead of physics solutions. Some of those jumps were in there for me to test out how the movement felt. I don't think I would put in overly difficult jumps in the early game in a finished product. There should also be some more platforms so you don't have to start the whole room over when you miss a jump. I'll keep working on it, so I hope you don't mind checking on it again later!