Eddie Riggs is the world's greatest roadie. When a stage accident causes blood to fall on Eddie's belt buckle, it transports him back in time to an epic age of heavy metal. There Eddie must fight his way through the hordes of the demon Emperor Doviculus to free humanity.

Brütal Legend is set in a free-roaming world inspired by heavy metal album covers, with the primary mode of transportation around the world being Eddie's car "The Deuce" (AKA "The Druid Plow"). Combat is mostly basic hack-and-slash, alternatively attacking with either Eddie's axe or his guitar Clementine. Through Eddie's guitar the power of rock can summon his car, melt enemy's faces, and even raise ancient structures left behind by the Titans. Many of the main missions, and the multiplayer mode, add real-time strategy elements to the mix. During these missions there are fan-geysers on the battlefield that can be harvested by summoning merchandise booths. Fans are spent to create units that can be commanded and even double-teamed with for devastating results. The ultimate goal of most of these missions is to destroy the enemy's stage before they destroy yours.

Upgrades can be purchased for Eddie's combat abilities and his car from The Guardian of Metal at the center of the Earth. The upgrades come in exchange for Fire Tributes that are collected by completing main and side missions, and finding the various collectibles around the landscape.