I need either both and if you're one of them then I need you to help me on the following game modes that I never finished:
Modern Warfare 2 (Spec Ops)
Gears of War 2 (Co-op on a harder difficulty, collect all the collectibles and one of the hordes)
Borderlands (One of the expansions, especially Mad Moxxi's Underdome)
Left 4 Dead 1 and 2 (Play on Expert difficulty and a few achievements)
Any Halo Game (Except for Halo 3 Co-op since I don't have it)
And a few more...
So, any help?