If you wish to play the Skirmish mode of the game please go to the game's installation folder:
- If the game was installed via GALAXY, please select the game in GALAXY, click on the icon on the right side of the PLAY button -> Manage Installation -> Show Folder
- If the game was installed via offline installer, then you will have to manually navigate to the game installation folder, by default it's: C:\GOG Games\game-title\
Next, please find and open (with a notepad) the dosboxDK_single configuration file.
Next, please add (with a space between) -1player both to "keeper.exe " and "deeper.exe".
After that please save the file.
Next start the "Multiplayer game" through GOG GALAXY:
Once the launcher pops up please do not check anything here and just press "Start Game".
In game go to the "Multiplayer menu."
Once here, please select 1Player.
You should be able to enjoy the skirmishes now.