Freyr-O: All right, so I've integrated my Galaxy with my Steam and now I have a nice list of all my Steam titles inside Galaxy. Yeah, but what does it mean in practice? Can I actually play them "from" Galaxy? For example, if I press *Install* in Galaxy, will the game be installed in my Galaxy game folder or my Steam game folder?
This doesn't refer only to steam integration but also the other available integrations such as UPlay or XBoxLive, etc.
You will still need Steam, uPlay, etc, clients installed to install & play (and each client will probably install to their usual default place, eg, C:\Program Files\Steam\Steamapps for Steam, etc), what Galaxy does is simply "launch the launchers" with a shortcut link that in turn tells them to launch their games. Think of it like
Playnite - it's a "meta-launcher" that you could use it to launch DRM-Free games directly from any source - GOG, Humble, retail disc, etc, but for 95% of DRM'd stuff on Steam, all GOG can do is embed a
"Start the Steam / uPlay / Origin client and tell it to start this game" shortcut without really ever having direct control over that platform. This may disappoint some who were expecting "one launcher installed" but that will never happen precisely because of Valve, Ubisoft, EA's, etc, and game publishers addiction to DRM.
Edit: If you want every game from every platform in one folder on the disc, eg, C:\Games, then all you can really do is change
Steam's install folder from within the Steam client then repeat for other clients until they all point in the same place.