: GOG Galaxy allows you to "downgrade" or select specific versions. This is particularly useful if you want to stay on v1.4.4.9 for mod compatibility while the rest of the world moves to newer versions.

On Steam, you license the game. If your account is banned or Valve goes bankrupt (unlikely, but possible), you lose access. On GOG, you download an offline installer. You can burn it to a DVD, store it on a USB drive, or upload it to your personal cloud. That installer will work forever, on any PC, without phoning home to a server.

Steam forces multiplayer through Steamworks. GOG’s version supports direct IP connections. You can host a server on an old laptop in your basement without Steam running in the background. This is ideal for LAN parties or playing with friends via Hamachi/ZeroTier.