Sony announced that they've sold 2.1 million units of the PlayStation 4 exclusive shooter Killzone: Shadow Fall.

[NSS7]

Massively undertracked. VGChartz only shows 1.2 million sold. I dont think Sony sold 0.9 million digital copies.

Source:

NEWS | We've sold 2.1 million units of the #PS4 exclusive Killzone Shadow Fall globally! Thank you for your support! #4ThePlayers

— PlayStation Europe (@PlayStationEU) January 29, 2014