Saber Interactive's co-op zombie shooter World War Z has sold almost 2 million copies in its first month, according to publisher Focus Home Interactive.

The game launched on April 16 for Windows PC, Xbox One, and PlayStation 4, and managed to sell 1 million units during its first week on shelves. 

Notably, the title chose to launch exclusively on the Epic Games Store on PC, and had amassed 320,000 sales through the fledgling marketplace as of May 2, with Saber praising the game's performance on Epic's digital storefront. 

"We have had 70,000 people playing at once across all platforms, with very similar distribution among PC (Epic Games Store), PS4 and Xbox One," commented studio co-founder Matthew Karch.

"What surprises us is the fact that sales outside of the U.S. on the Epic Store have been so strong, with the U.S. being only one quarter of sales."