Cute little game - the music is a banger, holy crap. I liked the difficulty, it was not too hard, but also not trivial. Had a moment where I thought "maybe I take this speed potion, even though I will hit a rock because of it, it'll be worth".
Sadly, I don't really see the use of the limitation? Maybe I missed something.
Great job for making this in pure JS - you have more patience than me, hah. (Btw the game loaded instantly for me and I encountered no bugs)