What exactly is getting fused? Downloading the Fusion DLC will graft all of the campaign and multiplayer levels from Serious Sam HD into Serious Sam HD: The Second Encounter. That also means that multiplayer variants that were previously only available in 'The Second Encounter' (like Beast Hunt and My Burden) will now be playable using maps from the first game.

The best part is that if you already own Serious Sam HD, you'll get the Fusion DLC for free. Those who only own Serious Sam HD: The Second Encounter will need to pony up $9.99 for the add-on. A release date hasn't been provided yet, but you can check out the Fusion DLC details below.

Serious Sam HD: The Second Encounter 'Fusion' DLC
• Adds 15 campaign levels and 7 versus levels from Serious Sam HD: First Encounter into Serious Sam HD: Second Encounter for an all new level of mayhem!
• Play all your favorite campaign and multiplayer maps from Serious Sam HD: The First Encounter in the new game modes found in Serious Sam HD: The Second Encounter!
• Includes Co-Op Modes for First Encounter Maps: Campaign and Coin-Op
• Includes Versus Modes for First Encounter Maps: Deathmatch, Beast Hunt, Capture the Flag, Instant Kill, Last Man Standing and My Burden
• Includes Team Modes for First Encounter Maps: Team Deathmatch, Team Beast Hunt, Capture the Flag, and Last Team Standing
• Use the powerful Serious Editor 3 to create your own levels based on content from Serious Sam HD: The First Encounter.