@naltmank in Royal, yeah... you need to have a condition met to even unlock the last 1/3 of the game... and certain other conditions met in order to get the "true" (I guess best) ending.
It's a pretty short list, but it's in-game time sensitive, so if you really want to be sure to hit it, it's spoiler tagged below:
Reach Councillor Arcana (Doctor Maruki) Rank 9 before 18th November to unlock 3rd semester
Reach Faith Arcana (Kasumi Yoshizawa) Rank 5 before 18th December
Reach Justice Arcana (Goro Akechi) Rank 8 before 24th November
Refuse all offers presented by the big bad boss