15 or less is terrible. I won't buy a game like that.
20-30 is decent, it won't add a lot or take a lot away.
40-50 is good. It definitely makes me want to buy the game, even if it isn't that good.
60 + is fantastic.
Perfectly, I'd like it to be 60 hours storyline, 140 hours of side-quests.
That's the perfect. For a strategy game, it would be even more - 400 +.
Platformer would be more ala 150 hours main game.
To say it simply - a game CANNOT be too long.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS







