Unlockables:
Unlock the following bonuses by performing the corresponding tasks:

BONUS – HOW TO UNLOCK
Alternate underwear – Complete the NIRO, Kageyashi, and Rui routes.
Character models – Compete the game. Note: Each faction route will unlock different character models.
Otaku difficulty – Complete the game.
Noppo and Chibi mode – Complete the game under the Otaku difficulty setting.