Saves from standalone versions of Serious Sam 3 or HD may not transfer directly to Fusion.

Fusion retains the classic local co-op mode, which can be shared online via Steam Remote Play. ⚠️ Important Considerations

Launch The First Encounter , The Second Encounter , and Serious Sam 3 from one menu.

Better netcode for smoother co-op and versus play. 🌐 Online Connectivity & Version 440323

You generally must own the original games on Steam for them to appear as "unlocked" within the Fusion hub.

To play online with this specific build, consistency is key:

Improved rendering, 64-bit support, and Vulkan API integration.

While Fusion supports the Workshop, certain manual builds may require "SteamFix" files to enable multiplayer features.