In a few minutes, on my account you will see a new gam called Space Car 0.2, which will be up temporarily while the Game Jam is still going on, and will have all of the bug fixes you mentioned, plus more.
Viewing post in Space Car jam comments
It was a bit easyier but still pretty hard.
I think, what someone else wrote, that it should be possible to control the height of the jump, by pressing the jump button longer or shorter, would make it quite better! Also I think there is a bug, where the boost timer doesn't reset, when you press R. So you sometimes have to wait until you can use it after you restarted.