Depends, were you enjoying every minute of that time, or were you dying repeatedly against Minotaur/Medusa? x)
This game gives you a ton of play time. Don't feel bad about hours.
edit: I'm level 58, and about 25 hours in. But I've played every SMT so I'm used to the flow of things...
I'd say a good 2 1/2 hours were dedicated to constantly dying to some boss. The normal combat & story are quite enjoyable, so I'll keep playing. The balance sometimes just feels SO off. But this is my first SMT game, so it might take getting used to. Also, I take it the levels start getting easier to get later... I'm only at level 15.