A idea I had recently when It comes to Ballrace is a mode in which players can select a level that they wish to play. Like Memories 13 or Khromdro 11 and allow us to constantly play that said level over and over again.
It would allow the later levels of Ballrace to become more optimised and improved as if you want to play a level like Oasis 11 over and over again for a new time at the moment, you have to play the entire map to get to that one individual level.
In which you get two attempts and if you fail those attempts, which is probably is going to happen. You have to replay that entire level all over again. It would cut down on the time it would take to get back to that indidvual level.
This has probably be suggested before but It would be nice to see this become a reality.