I have the game, and beat it 100%, and these are the times i got playing it
Terra story:
Rushing (only story): 7 hours
Not rushing: 14 hours
Complete: 54 hours (I have 80 hours of gameplay right now because leveling up takes forever in this game)
Ven Story:
Rushing: 5 hours
Not rushing: 11 hours
Complete: 38 hours
Aqua:
Rushing: 9 hours + 1 Extra hour (Extra hour for something you might not want to know)
Not rushing: 12 hours + 1 Extra hour
Complete: 35 hours
So far i have now between all the saves around 145 hours of gameplay. So yeah, Nomura kinda lied a bit about how much the game lasts, the game's extras are little, and most of them not even challenging, at least to me, and the secret boss is completely dissapointing, i hope they do a better job for the extras in the next game.