This is also using SHTUP.

I noticed that on the main menu the button labels are shifted a bit to the left... and it's the original release main menu, not the multiplayer-enabled main menu. Is multiplayer disabled in the current GOG/Steam release?

Yeah, it uses a different file for the button layout. Apparently we never fixed it because the non-multiplayer menu is basically a relic from before the first official patch so why bother.