This is the quick guide for you. I assume there are others like me but I use other tools to manage my DOSBox and SCUMMVM games. I love using Steam for keeping track of how much I play and when and use the overlay a lot. For these older games, using the emulation software directly gets you a lot of benefit like custom tuning. I do this type of thing for nearly all my dos and older games.

I was not able to get saves to work from the Steam Dig moved over to the full ScummVM. I'm sure there's a way but I just started a fresh game into the ScummVM version.

Without doing extra configuration in ScummVM, Steam save syncing will very likely not work. I'm sure there are a couple tweaks we can do to make this work. (Comment if you found a way.)

Let's start with some default directories. Let's assume my steam library is (we'll call it %STEAMLIB%):
C:\Games\SteamLibrary\steamapps\common

Scumm Library is (we'll call it %SCUMMLIB%):
C:\Games\ScummLibrary\

SCUMMVM install directory (we'll call it %SCUMM%):
C:\Games\ScummVM\

(These are not real environment variables I'm just using them as examples and shorthand. How you have your steam libraries setup will be a case by case scenario.)

All of these steps should work the same in Linux as well just pay attention to the paths and you should be good.

This should put the game in "%STEAMLIB%\The Dig"

Copy the entire directory "%STEAMLIB%\The Dig" into %SCUMMLIB%. The resulting directory should look like "C:\Games\ScummLibrary\The Dig"

Copy the following files from the SCUMMVM install directory into "%STEAMLIB%\The Dig". You could try to use the versions of the files that are in there but you may have version mismatches. It's better to use the versions of the SCUMMVM you're going to be running.

• discord-rpc.dll
  
• SDL2.dll
  
• SDL2_net.dll
  
• WinSparkle.dll

(You could also hard link these files too if you want but they're so small I just copy them in.)

Windows->Run cmd.exe (must do this as Administrator)
cd "%STEAMLIB%\The Dig"
mklink /H "The Dig.exe" "%SCUMM%\scummvm.exe"

The pupose of this link is to let Steam launch "The Dig" but what it is actually doing is launching ScummVM.

(Please remember these are not actual environment variables. Use the full absolute path.)

Launch ScummVM however you want.
Add Game. (Make sure you're using a version that supports The Dig...since ScummVM 0.2.0.)
Choose the %SCUMMLIB% directory.
Change whatever settings you want within ScummVM for the game.

At this point, you should be able to launch within Steam.