このコンテンツについて

Digital Artbook containing concepts and previously unseen images from Level Zero: Extraction

To access the Artbook, right-click Level Zero: Extraction in your Steam client → Properties → Installed Files → Browse
You will see the Artbook (.pdf) in the game's folder. Like this:

大人向けコンテンツの説明

開発者はコンテンツを次のように説明しています：

The artbook might contain images not suitable for all ages, such as realistic depictions of weapons, alien monsters, and blood.