However this does not happen if you skipped the scene or decided to go back to sleep during Vanni's arrival cutscene.
Cheat Codes can be earned by getting different endings.
Talking to characters will increase your Relationship with them.
The goal of a dating sim is to raise your Relationship with characters and after falling in love, to have a happy ending with them.
Raising your Relationship can be done by talking to them, giving them gifts and going on dates.
(50% if Vanni is on board) You can exit the hall or enter another room and try again if this happens.
Ai is your average girl, who lives in Reton with her constantly working parents.
Like gift giving, you can't go on dates without talking to a character for a while.