Because the game relies on invisible meters, getting a specific ending requires sticking to a specific personality type throughout the game.
How to get the Yukino Route:
How to get the Yui Route:
How to get the Iroha Route:
How to get the Bad Endings:
Without spoilers, the Zoku game includes an ending that directly challenges the anime’s conclusion. It is controversial, emotional, and arguably better written than some light novel volumes.
Not-so-good aspects: