Quickly press R3, L3, R2, L2, R1, L1, Square, Triangle, Circle, X, R3, L3, R2, L2, R1, L1, Square, Triangle, Circle, X at the title screen.
Alternate Costumes
Have a saved game file from The Oanechan Bara to start with Saki's, and all of Aya's original five costumes unlocked.
Aya 2
Complete two quest mode quests in story mode.
Aya Original Costume 1
Complete five quest mode quests in story mode.
Aya Original Costume 2
Complete six quest mode quests in story mode.
Aya Original Costume 3
Complete seven quest mode quests in story mode.
Aya Original Costume 4
Complete eight quest mode quests in story mode.
Aya Original Costume 5
Complete nine quest mode quests in story mode.
Hard Mode
Complete level 6 in story mode under the normal difficulty setting.
Makoto
Complete level 6 in story mode as Riho.
Makoto 2
Completely fill the ???? gauge.
Riho (17)
Complete ten quest mode quests in story mode.
Saki
Complete level 6 in story mode as Aya.
Saki 2
Complete three quest mode quests in story mode.
Saki Original Costume
Complete four quest mode quests in story mode.
Violent Mode
Complete level 6 in story mode under the hard difficulty setting.
Wallpaper 1
Complete one quest mode quest in story mode.
Then, press L1, L2, R1, or R2 at the mode selection screen to switch to the new wallpaper.
Wallpaper 2
Complete level 6 in story mode under the hard difficulty setting. Then, press L1, L2, R1, or R2 at the mode selection screen to switch to the new wallpaper.
Wallpaper 3
Complete level 6 in story mode under the violent difficulty setting. Then, press L1, L2, R1, or R2 at the mode selection screen to switch to the new wallpaper.