i know shenmue 2 has some Secret events, like the duck racing, shopgirl fight and birthday scene etc.
I am unsure if it is possible to do all of these events in one play through as events need to be done by doing certain things on certain days .. so you would probably not be able to hundred percent complete it (?)
Wonder if there will be any achievements for this sort of stuff in the HD releases. I hope the achievements aren't just for basic shit that you have to do anyway. I hate achievements like "Beat the 1st Boss!". The achievement system should be based around showing your actual skill and know how of its respective games.