When you beat story mode, you unlock 2 new features: A sound test, and another story.
Sound Test lets you play all the tunes from the game, while watching a dance robot grooving to the beat.
Another Story is a very short mode that lets you redo some of the love scenes from the main story, but instead of wooing the main love interest, you are now a robot trying to woo the rival girl.
Beating certain scenes allow you to play new games in Time Attack/Survival challenge mode.
Press Down+Y in the title screen, you will be able to record your voice for 3 seconds. Press Down+Y in the title screen again to play it.
On your birthday, Christmas, or at new year the girl wishes to you for that day.
To unlock Hair color, you must find 10 rabbits.