Thanks for playing and the detailed feedback!
Three lanes is a level that is amusing to watch others play, I think it is ok to put those kind of levels every once in a while.
Rewind is something that has been suggested, but it is really not something easy to add to a game that has continious play. I should have planned the game from the very start to include and right now it is not possible to add it without having to code everything from scratch again.
You are right, priorities could have better tutorial text. It also showed me that the mechanic is not as intuitive as I thought, so I might need to think how to explain it better.
I will need to redesign Four for four.
I realised just now the level selection is bugged and the three last bonus levels don't unlock on their own. To unlock them, go to pause the game, go to "skip levels" and then "unlock all levels". I updated the demo but it wont fix profiles that beat the last level already.