The Verdict is in -- SACKBOY STRIKES BACK! 670K Week 1 WW (wk 0 + 1 in NA)

[Kantor]

That may be very good, especially for a new IP, a 2D sidescroller on an HD console.
But it's not huge. It's less than a third of what Gears 2 got and slightly less than Fable II.

I think it will have outsold Fable II WW within a year, most probably sooner. But it's not going to touch GeOW 2.

Shame.