Killzone Shadow Fall sales exceeded 2.1 million units as of January 15

Obviously, Sony is rather pleased.
“I am thrilled that so many users have been enjoying KILLZONE SHADOW FALL since the launch of PS4,” said Sony Worldwide president Shuhei Yoshida. “This title fully embraces the creativity of the development team at Guerrilla Games based in the Netherlands, and is a great representation of what SCE WWS has to offer.
“SCE will continue to deliver exciting software titles, and is currently developing more than 30 titles including DriveClub, InFamous: Second Son and The Order: 1886, which offer entertainment experiences only possible on PS4.”
SCE will “continuously expand the world of PS4 through the introduction of attractive software titles,” it said.