The Legend of the Beast has three parts; a small campaign, three new versus levels, and one new survival level.
Additionally, the DLC also coincides with Serious Sam HD: The Second Encounter's Versus and Survival modes going free to play. This includes Deathmatch, Team Deathmatch, Insta-Kill, Last Man Standing, Team Last Man Standing, and My Burden.
The campaign consists of three levels and features Serious Sam looking for the "Ram-God" of The Grand Obelisk. The campaign takes place in Ancient Egypt, and is set in the events that happen after the Metropolis level of Serious Sam: The First Encounter, but before the events of the Alley of the Sphinxes.
It appears that the Sign of Amon-Ra wasn't in the Temple of Ptah in the Metropolis, but instead it is located somewhere in The Grand Obelisk. Though, there is a legend that a beastly Ram-God roamed the area, terrorizing the citizens. After clearing his way through the city, Sam finally reaches the Obelisk, defeats the Ram-God, acquires the Sign of Amon-Ra and proceeds with his journey.
- Elephant Playground
- Forest Run
The first and the second versus levels can be played in Deathmatch, Team Deathmatch, Insta-Kill, Last Man Standing, Team Last Man Standing and My Burden modes. Forest Run can be played only in Capture the Flag mode.
- Triple Trouble
The new survival level (Triple Trouble) is similar to Bear City, having the player in a "fortress", while attacked from the north, west and east. The fortress is armed with grenade launcher turrets and triple minigun turrets, which can be activated by shooting the targets on the fortress for each one respectively.
- Croteam confirmed that in the game files, the 3 campaign levels "CityEnter", "CityMiddleYards" and "CityObeliskYard" are the first 3 levels from the Beta.