GRAW 2 for the PSP is worth your money especially if you have a friend to play it with.
In GRAW 2 you play as Scott Mitchell, but instead of just being dropped off to do your next mission, you find yourself crashed in a enemy filled jungle area. From there you must do as you're ordered and once again succeed. It's basically what you'd expect from the GRAW series, little has been changed, but you can obviously tell the huge differences from the Next-gen consoles. The biggest and most obvious difference is that you no longer have a squad with you, your basically a lone wolf packed with a longer lasting life and plently of ammo. It may sound hard but it's really not, you'll find yourself flying through the game with perhaps a few stumbles here and there but not many. The other differences is the cover feature, you cannot take cover with your back to a wall and pop out to shoot. Instead you have to rely on your crouch and prone stances and standing behind the closest object you can find. But with your health lasting longer than usual and gradually healing, you shouldn't find this at all annoying.
Now once you've completed the campaign and you may think of selling the game, think again as GRAW 2 also gives you a brilliant co-op mode where you and your friend can choose your character, weapon and map and play the campaign together, or even play another mode where you can see if you can hunt down as many enemies in the limited time given. These modes can also be played on your own.
GRAW 2 for the PSP is worth it's money as it's not a horrible attempt but a rather decent one and should be at least rented.