I really liked Okami, but I never finished it. Unlike most folks, it wasnt even the padded hour count that got me-- I dropped it about 2 hours in. Its beautiful and I liked the drawing gimmick but for some reason, I just couldnt bring myself to play more.
Dark Cloud is probably a game I consider my personal favorite PS2 RPG game but I have never been able to clear the epilogue chapter because of how much of a leap in stats the monsters get. To this day I still havent cleared it.