As a fellow - but recently a bit inactive - P&C player I can only say: Thanks xlynx, that's awesome! Maybe I'm adding some notes of how to run AGS games on other platforms (and move them to a new section) as the GOG.com versions are running fine under Linux with little help.
Did you also test games from Daedalic? I can't get them run without Steam, but maybe that's just me.
Offtopic: What's your favourite P&C?
The Windows Steam versions of AGS games have a dependency on AGSteam.dll (for achievements and such) so they won't work out-of-the-box on Linux like the GOG version. There's two solutions though: either run in Wine, or run under Linux AGS using a native substitute for AGSteam.dll
Some AGS games (Gemini Rue, The Samaritax Paradox, Quest for Infamy and The Shivah) are already officially on Linux. I haven't tried, but I imagine downloading these under Linux Steam, would allow them to work Steamless out-of-the-box.
I've got the GOG versions running under AGS for Android
, but no luck with the Steam versions due to the aforementioned dependency.
I tested Daedalic's "The Dark Eye: Chains of Satinav" and "A New Beginning" but they just play dumb.
My favourite P&C? oh man... If you're looking for recommendations PM me with your tastes as it's a whole topic on its own!