I liked this game. It takes a while to get use to the combat system, but when you do it becomes quite enjoyable. I agree it was too vague in-game, but that's what GameFaqs is for. And yes, it was hard, but that just makes it satisfying to beat. I nearly quit at the Thunderbird, but I pushed on, and it was great.
As a note, I have a friend who claims to have beaten it in four consecutive hours. I trust him not to lie to me, but...I mean, man...