Not that i saw? I thought i found everything but i was still short like 5 manuscripts and a couple radio broadcasts. I might have to run through it one more time. i think i missed some achievements. You also unlock a couple gamer pics and avatar outfits. All in all i would say its worth $15 all day.
My only complaint is that ammo isn't as scarce as it was in the first game. You will probably never run out of ammo which kinda takes away from the "oh shit" factor...