Not fond of those Co-op and Terror is Reality achievements. Half the achievements I've never obtained are almost always down to online/Co-op achievements. Only upside is if the game is split-screen (which I highly doubt) as that way I won't need someone else to own the game.
100% Club: 22
Retail: Assassin's Creed, Assassin's Creed II, Call of Duty 4: Modern Warfare, Call of Duty: Modern Warfare 2, Dead Rising, Dead Space, Fallout 3, Hitman: Blood Money, Halo 2 (PC), Halo 3, Halo 3: ODST, The Elder Scrolls IV: Oblivion, The Orange Box
Arcade: 1 vs 100, Battlefield: 1943, Dash of Destruction, Dead Rising 2: Case Zero, Doom, Portal: Still Alive, Rez HD, Shadow Complex, The Maw