Google used WebSockets, HTML5 Canvas, CSS3 and the touch API
The Google Chrome Super Sync Sports is a fun little game, but the technology behind it is what's impressive. The game connects mobile clients, which work as game controllers, to a desktop browser which works as the screen.All of this happens over the web, using standard web technologies and in near real-time. Developers familiar with new web tools should be able to guess at what's underneath, but seeing it all working together and working so well is impressive.
The data communication, which carries the touch input data from the phones and tablets to the desktop browser, is handled by WebSockets, a technology designed for just this kind of scenario. Mozilla itself used it for its own experimental pure HTML5 MMO game.
All of the cute and responsive graphics are handled by CSS3, SVG and HTML5 Canvas. Finally, the Touch API translates your frantic finger gestures into motion.
Google plans to have an article detailing all the technology and how it was put together on the HTML5 Rocks website, but it's going to take a few more weeks.