Looking for PSP games...?

I like to play games like GTA, Resident Evil, and Zelda. I got a Sony PSP a while back and I got the 3 GTA titles for it (which are all awesome). And even longer back i got Ratchet and Clank Size Matters and Chains of Olympus. However, I've beat all of their storylines and am looking for a new game or 2 for the PSP. So judging by the types of games I play, I was wondering if anybody could give a few recomendations.