It's an initiative to stop game companies (EA, Ubisoft, Blizzard etc) from being able to decide if you can play a video game that you've bought. The example used is for the video game "The Crew" which was an online-only racing game. After the servers were shutdown by Ubisoft, the game that many people bought became unplayable.
What StopKillingGames wants, is that any company that publishes / develop games provide a way for people who own the game to continue playing it indefinitely. This would most likely come in the form of a game server that could be run by any owner of the game, and shouldn't be a requirement that publishers / developers run the servers forever as that would be unsustainable.
What a load of crap. Let people choose for themselves how much carbon they believe that they should emit. Someone somewhere is trying to make it harder and harder to emit carbon. Red flag right there.