The Ingress closed beta started back in November of 2012, and the game made it to general release back in December of 2013. Since its creation, the game has gathered a cult following, and built a very detailed backstory. The game itself is described as something of a cross between capture the flag and risk where the game board is the Earth itself. It can be daunting for newcomers, but Google is hoping a new video will make it more accessible.
The video runs through the basics of the game, even covering the relatively unnecessary mechanic of how to capture a portal. The game has been running long enough that all portals have been captured at this point, and any new portals are snatched very quickly. Still, it is nice to see a simplified explanation of hacking, resonators, XMP bursters, and control fields.
Of course, this is just a description of how to play the game itself. If you want to dive into the story behind Ingress, there is a ton of media at the Niantic Project website, over 100 videos on YouTube, and even a handful of novellas in the Google Play Books store.