This "optional client" will allow users to play games without needing to connect to the internet.
"We believe gamers deserve a better experience," the trailer's narrator said.
"With GOG Galaxy, your game will always launch. No online activation required ... Being online will always be optional."
If users wish to play online with friends, they'll need to connect; sharing achievements online with friends will also require a profile. GOG Galaxy will also include a cross-play feature that allows them to game with friends who have titles on other online venues.
Check out the trailer above for more on the service. Additional news is expected this year, and those interested can sign up on the service's website to participate in The Witcher Adventure Game's closed multiplayer beta.