Thanks for reviewing the game.
Good points, I've adjusted the game to be better based on them.
Abyss fall detection now should be triggered faster, and resetting position should work better, including new sound effects.
Hud text will now resize together with the window, so for big viewports you'll have proportionally big text.
About loosing the car in mid way... not sure how it happened for you, however I've added a hint that ENTER will reset the car position even if the player is not in it, returning it to the last moment when it was on the ground. Together with better player position reset it should eliminate unexpected prolonged walking exercises.
As for the jumpiness.... I've added it, however I'm not sure about the result. Actually, I think it's more challenging for the code than for a player... but maybe it's still fun.