Slimebeast on 01 June 2008
The OP has a point. MGS4 is a niche game. Sneak games don't have the broad appeal that many other genres have (like FPS, regular action-games, button-smashers).
But it's a big huge niche game. It will sell close to 5 mill.
Will MGS4 move consoles? Yes, mainly to those who love the franchise and decided to buy a PS3 when the game is released. But it also helps the PS3 game library to get more complete, another genre spot will now be filled by an AAA title. So in the long-term sales, the game is significant, it's just those type of sales that are near-impossible to track because they are so spread out in time.
