Saber Interactive and Focus Home Interactive today announced the release of a free World war Z update, Proving Grounds. The update features Weekly Challenge mode, a separate playlist with unique gameplay modifiers designed to dramatically change your play style and keep the struggle against the undead dangerous and exciting each week.

Completing the weekly challenge rewards players with a new currency that can be spent on character customization options like color schemes, headgear, backpack attachments and more. The update also includes the new FN FAL battle rifle, as well as a variety of game fixes and quality-of-life improvements.

In addition, players can now purchase the “Biohazard Bundle” DLC bundle for $4.99, featuring three new weapon skins and a tomahawk axe.

The Proving Grounds update rounds out the first season of free content for World War Z, which included “The Undead Sea” Tokyo mission and the six-skulls extreme difficulty setting for all chapters. Season two, coming soon, will add a new survival mode, PvE maps, special zombie, gameplay updates, and even more skins.

World War Z is currently available digitally and at most major retailers on PlayStation 4 and Xbox One, as well as Windows PC via the Epic Games store.