I had the same problem with with L.A Noir on my PS3 once. It would not read so i just sent it back and reput it in my GameQ and when i got it again it read just fine. So just send it back and reput it in you GameQ.
Metal Gear Solid 4 Guns of the Patriots. When i had to fight Vamp i could not find out how to kill him. I put a LOT of rounds in him and i died a LOT. Untill i had enough of it and got on Youtube and learn how to kill him.
Yes! i just got it today and i have been playing it for a few hours now and i love it! it's like the firs just with new characters, gun, enemies, ect. and a whole new world to play in! It's definitely worth buying if you have no got it yet.