What better way to cherish the holidays than with mullets, machine guns, and mutants? 3D Realms’ sci-fi platformer, Bio Menace, joins GOG.com’s collection of 14 free classics, which includes Beneath a Steel Sky, Ultima IV, Lure of the Temptress, and Akalabeth: World of Doom.

For you last-minute shoppers, the Happy Holiday Sale is offering up to 75% off every game from the Bethesda catalog. This includes 75% off the classic Fallout games and retro shooters: Wolfenstein 3D & Return to Castle, The Ultimate DOOM, DOOM II & Final DOOM, Quake I-III. Finally, explore The Elder Scrolls (66% off) history with classics like Morrowind, Battlespire, and Redguard.

As always, any purchase from the Bethesda catalog on GOG.com comes with a free copy of The Elder Scrolls: Arena and The Elder Scrolls Chapter II: Daggerfall.

The Happy Holiday Sale ends on December 29, 4:59 AM GMT.