
I discovered the above easter egg just recently. I've found that it has since been described by others, including by Lifehacker's Patrick Allan.
Amit Agarwal wrote about the game at Digital Inspiration when a tipster mentioned the discovery, and it's actually pretty fun! When you reach the "Unable to connect to Internet" screen in your Chrome browser, just hit the space bar to start the game and use the space bar to jump over incoming cacti. The game works on the Android version of Chrome as well. Just turn on airplane mode and tap the screen to start jumping. Instead of getting mad when you can't get a connection, you can blow off some steam playing an addictive game. My high score is 1,081—bring it on.
My score is not that high, yet.