I was expecting ScummVM only release, whitout executable files (like it was with Kyrandia games). But in the game instalation directory there is a catalog named "other" with rest of the files.
After copying all game files to a new catalog and renaming MONSTER.SOG to MONSTER.SOU game can be launched in DOSBOX! :)

I haven't got any dialog or text, but music is playing and game is working :) Now I must just figure out how to enable voices.
Not that I'm complaining for ScummVM but it's good to know that we have "FULL" game :)

The SOG file is an OGG compressed version of the SOU file, which is only supported by ScummVM.

I don't think you can convert this back to the format used in the SOU file using standard ScummVM-tools. That's why it would actually be better if GOG could offer the original MONSTER.SOU files for the LucasArts talkie games, instead of the compressed versions.

Yup. That explains it. So not so FULL game as I expected.... Community wishlist? :)

You can get the dialogue text to show up by either starting the executable with the "t" argument:

ATLANTIS.EXE T

or hitting ^T (CTRL+T) during the game.