: Open SmartSteamEmu.ini and set AppId = 41070 . Point the Target path to your Sam3.exe .

: Rename the original steam_api.dll (or steam_api64.dll ) to something like steam_api.dll.bak . Copy the Goldberg version into this folder.

: Open the game executable directly. Go to Network Play > Cooperative (or Versus) > Start Server . Other players on the same network should then find your session under Join Game > LAN . 2. Using SmartSteamEmu

Playing via LAN typically requires a connection to the Steam backend to initialize the network menu. However, you can bypass this requirement using Steam emulators that redirect network calls locally. 1. Using Goldberg Steam Emulator (Recommended)

: Find your Serious Sam 3 installation (usually in Steam/steamapps/common/Serious Sam 3/Bin/ ).

The Goldberg Steam Emulator is a popular, lightweight tool that replaces the standard steam_api.dll to allow LAN play without any Steam client running.

: Create a text file named steam_appid.txt in the same directory and paste the number 41070 inside.