i just get this idea. how about an Arcade mode? the current Solo mode seems to be a Hi-score mode. why not stack them in one single menu? along with other possible single-player modes. the arcade mode goes like this: you choose a mode(osu!, Taiko, CTB or Mania) then a difficulty(higher difficulties could be locked until further progress), then a beatmap set(Set A, Set B, Set C, Set D, etc). Mods could be locked until further progress or not. you complete the maps of the set you choose, al in a row. if you lose on a map, you'll lose a life and you'll have to restart it from the beginning. lose all lives and its Game over. when you clear the set, the lives remaining will add to your total score. of course there will be leaderboards(top 10 i think it should be)