DOOM: 10 Things You Didn't Know You Could Do

4. Find Old-School DOOM Levels

Tucked away inside each one of DOOM's newer levels is a throwback to the original - yes, the blocky, polygonated original that reminds you just how far the industry has come in the last two decades.

Located by interacting with various secret parts of the environment (the first is a lever inside the molten metal-filled Foundry), you'll then reveal a doorway that lets you literally just walk into these areas and start shooting.

Sadly, the enemies you'll go up against are from 2016 DOOM, as are your hands and weapons (it's the same trick Wolfenstein's reboot played back in 2014), but at least demon placement in these corridors matches their original layouts.

Bonus fact: If you die inside these areas by being blown up, Doomguy's head will feature a pixellated model inside the helmet, which is also the same as the original sprite.