Bethesda have announced that their 32-level pack Doom Zero has been officially released as an add-on for the recent re-releases of the iconic FPS classics Doom and Doom II.

Doom Zero was initially made to celebrate Doom II's 25th-anniversary last year and this pack contains new bosses, new sounds, new enemies, as well as some brand new sprites. The mod also offers a lot of challenges that are ought to put your brain to the ultimate test.

You can get Doom Zero for free via the add-ons menu in Doom and Doom II on Xbox One, PlayStation 4, Nintendo Switch, and PC.