In the world of gaming, there is always the question of how long you can stand repeatedly playing a certain game? Some games, such as the World of Warcraft series, keep releasing updates and expansions to keep you interested. Others have so many secret levels, quests, and point systems that it could take you years to even find them all, nevermind complete them(unless you’re cheating with a walkthrough or something. I never did get all of the hearts in The Legend of Zelda: Ocarina of Time)
Then you have games like Ghost Recon: Advanced Warfighter 2, that have none of the above, but make addicts out of us all.