GTA IV needs little introduction; its Rockstars flagship title, and even the single player campaign alone represents a decent chunk of your time. But start factoring in the activities its possible to get involved with, the sidequests and races, and youre already probably doubling the length of your experience. Why Youll Never 100% It: If youre interested in attaining every achievement, youll not only need The Key to the City achievement/trophy (for 100% Game Completion) youll also need to spend weeks online winning races, deathmatches and generally building towards the infamous Auf Wiedersein Petrovic achievement/trophy awarded for winning all ranked multiplayer variations, all races and Cops and Crooks, as both sides. Is the reward worth the immense effort? Probably not, but if youve fully clocked this one, you have my respect forever.