I believe that you are fast. I do not believe you that you finished this game in 1 and a half hours from front to back. Just the minigames themselves would take up a big chunk of that time.I do. I've been reading a lot from an early age and now I read very, VERY fast.
There's a good amount of content here. I don't really have a number, but you should be good for quite a few hours. But like he said: Play 3.6Damn, I'm a really slow reader so I don't know what to think now lol.