Set the following environment variables according to your setup, change the folder to your Diablo II folder. This can either be done in the environment variable tab, or open up powershell as administrator and run the following commands to set it system wide:
⚠️ I suggest using a clean Diablo II 1.13c folder you are not using for anything else for this, since it will override txt files in this folder when either running scripts or debugging with Visual Studio.
⚠️ Make sure 'game.exe' has compatability mode set to Windows XP (Service Pack 2).
[System.Environment]::SetEnvironmentVariable('DIABLO_DEBUG_FOLDER','C:\Program Files (x86)\Diablo II\ProjectD2',[System.EnvironmentVariableTarget]::Machine)
You can change the command line arguments as you see fit.
[System.Environment]::SetEnvironmentVariable('DIABLO_DEBUG_COMMAND_LINE_ARGUMENTS','-w -ns -direct -txt',[System.EnvironmentVariableTarget]::Machine)
Any debug or changed version will only work in Single Player. Do not enter multiplayer with a modified BH