DOOM: 17 Easter Eggs, Secrets & References You Must Find

10. The Melting Thumbs Up - Terminator 2

Visible in early footage of the game, this subtle nod to Terminator 2 will only trigger if you let yourself die in the Foundry's lava pits, however it's so awesome you'll at least want to do it once.

Melting to death through white-hot lava results in Doomguy putting one thumb up as he slowly descends into the liquid, a reference to the close of Terminator 2, where Arnie's character does the same as he's lowered into a smelting chamber.

Bonus fact: This scene was also referenced in Mortal Kombat: Shaolin Monks, where after booting Scorpion into a fiery pit of death, he too sticks up his thumb on the way down.