Maaan. Sorry, @nijimeijer , but @Ryan_Kelly just barely snuck in before you.
It is indeed the newest version of the Sega Mega Drive & Genesis Classics menu on Steam. It's really awesome, actually. Really makes you feel like you're there, playing the games on an actual console and CRT. It's so much fun. It zooms in on various elements of the interface. The only thing I wish it had was full first-person control to walk around and look around this little bedroom, rather than being restricted to specific scripted movements. It only has those games, because those are literally the ones I own on Steam. If you had a bigger collection, those shelves would be more filled in. It's so cool. You can change the time of day, all kinds of fun things. I'd really like to try it in VR some day.
Here's a random video of it I just found on youtube to show you.