By utilizing a Cutscene Break you can exit the level early, before the game has finished giving you all of your Crystals. For example, if you exit when your Crystal count has only reached 99/100, the 99 will be added to your SMP Card, then you will enter 4-4 Goo Man Chu’s Tower with 1/100 Crystals. You can then complete Tower with 101/100 Crystals, so you are still able to collect all 100 crystals in each level. This was discovered 2020-02-09 by Paulmall, and we ruled that it is OK for Max% runs