This is pretty good.
save anywhere, all the moves from the early games, a cool story line, a riddick style prison break, impressive graphics, authentic voice acting
bad stuff:
game crashes loads when you try to save in big rooms ( a pain in the ass as you have to reset the PSP)
the loading times are huge, about fifty seconds for each loading screen. whenever you load a game from scratch you hav to sit through three of 'em.
sound screws unless you hold the PSP exactly upright, so you can't see the screen
no brightness adjustments, you'll almost always be wearing nitesites.
but, regradless of that, it's great game that you should give a try if ya find it going cheap. i wouldn't pay more than 12 quid/15$