A game that is overrated would have to be Any guitar hero game/Red Dead Redemption.
For Red Dead Redemption the game just had such high standards that it was just wasn't enough to reach them. Even though the game is great.
As for Guitar hero, how can you get such high ratings from a game in which has okay/mediocre graphics compared to other games. Like seriously the only controls you have are hitting like five buttons in a row to match the rhythm on screen. Don't get me wrong I love the game, but there's only so much praise you can get for it.