how is it possible max% is more complete than 100%?

i'm not a runner btw and it's been a while since i played but i remember there were secret stages and a better ending after some stuff

In 100% we only get what the game requires us to get for our save file to display 100% at the end. It doesn't require getting 100/100 crystals in each level or collecting every heart pot, so that is what we do in Max%