I probably spent about 10 hours into Ghosthunter for the ps2. I kinda liked it, but I wasn't having much fun playing it. Recently I've tried MGS: PO (5 hours), before I decided the psp controls suck (sold it quickly). I finished MGS 2, but that was a complete waste of my time (if I can say that about a game). After I stopped playing with Snake, everything was just not fun. Raiden sucked!
Oh, Virtua Tennis for the psp. I spent countless hours on that game, back when the psp library sucked completely (it still sucks somewhat). I got to the level where you play King and Queen, and I stopped having fun. I could defeat all other opponents easily, but levelling up just to beat those cheap bastards became too tedious.