The video you saw is most likely a kodi install with pleXMBC, the advanced launcher add on, and a custom menu setting. No official Plex product will give you this option.
I think it would be a good idea for Plex to keep up with other products like Kodi to have a games section that emulates retro games like NES. If they could support multi-playing with your Plex friends as well I think it would do wonders for there subscription fees.
I think it would be a good idea for Plex to stay true to its roots and main purpose, as opposed to trying to be a “jack of all trades, master of none”. If you want to play games, buy a console or build a gaming box. There are a myriad of solutions that are inexpensive and would provide a far-better gaming/emulator experience than for Plex to try and shoehorn such functionality into an existing software framework never designed for such a purpose.
I can’t ever see the Plex doing this. This would be just asking for a legal battle with Nintendo, Sega, insert company here. Nintendo still sells NES and SNES titles on the Wii and Wii U as virtual console games.
Don’t get me wrong, it would be a lot of fun, I had my PSP set up with custom firmware and emulators for NES, SNES, Genesis, and a host of others with a huge library of games, and it was much fun.
But you know, it wouldn’t be the end of the world if they included a program launcher in the desktop software. Which is more or less what the original poster was talking about (and didn’t know it).