VGChartz writes: "After debuting as the fastest selling PS3 game in Japan, Metal Gear Solid 4 had an enormous drop in sales according to the preliminary data. Because of the drop, Metal Gear Solid 4 was the third best selling game of the week.
Metal Gear Solid 4 had the biggest week one to week two percentage drop in the preliminary data since these articles have been posted, a time frame of over a year.

Full story: n4g.com