I have played and finished the single-player campaigns of:
Siphon Filter: Dark Mirror
Daxter
Resistance: Retribution
Crisis Core: Final Fantasy VII
And i love them! Yes, they're older games but they still look and work like charms. From the adventures of the fun-loving Daxter, to the emotional climax of Crisis Core, I have traveled through different worlds, with just a PSP in hand. I am happy for this experience. If you want to know my view on some of these games that I've played through the first two weeks of summer here in our country, check out my reviews.
More power to the players!