As the result of union negotiations, it was discovered that Telltale Games was working on a Guardians of the Galaxy game. Well, it's no longer unofficial. During the 2016 The Game Awardsshow, a short teaser was shown confirming the cosmic Marvel title. Here's the teaser:
As noted, it will utilize the episodic structure of many a Telltale game, in this case, the Guardians' tale will have five parts. Kevin Bruner of Telltale Games provides a short description of the game:
"In Marvel's Guardians of the Galaxy: The Telltale Series, players will take on multiple roles within the ragtag band of heroes, and take the pilot's seat in directing their escapades around the universe."
The game will release in 2017 and will be available digitally on home consoles, PC, and mobile devices. It will also appear at retail on a season pass disc with the first episode on it, and subsequent episodes released as they become available to download.
For more information (well, eventually it's only a teaser page right now), you can check the game's home page.