Killzone developer Guerrilla Games’ new action-adventure game Horizon: Zero Dawn has crossed a new sales milestone. PlayStation boss Shawn Layden said in a new interview that the game has passed 3.4 million copies sold, up from 2.6 million units sold in its first two weeks.

“We’ve been so proud of what that studio has been able to do,” Ryan told Glixel. “It’s a brave step for that studio to go from making shooters like Killzone to an open-world game.”

Given the big success of Zero Dawn, it’s no surprise that the developer is supporting the game with a new story expansion. It’s possible Sony will discuss or show this off at E3, though that is not confirmed at this stage.

Additionally, Sony confirmed that nearly 3.4 million copies sold, 915,000 were digital.

“This kind of shift changes everything. It changes the publishing model, it allows smaller players to put out games, it affects DLC and it has a huge impact,” PlayStation boss Shawn Layden said.

Also in the interview, Sony discussed PS4 Pro sales. While a unit figure was not disclosed, Sony said around 40 percent of PS4 Pro sales are from people upgrading from the standard PS4.

“People just want the best,” PlayStation Europe boss Jim Ryan said. “Maybe they just want to future proof? I think we see the same thing from Apple customers too–there are people that want the best that you can buy.”

You can read the full interview here at Glixel.

Keep checking back with GameSpot for the latest on Sony, as E3 2017 is right around the corner and there is sure to be a lot of big news coming.