A secret text adventure game has been discovered in the source code of Google Chrome.
While not exactly complex, the story - which is a mission to locate the missing letters of the Google logo by way of simple text directions - requires you to navigate by way of a series of directional instructions, plus the actions "grab", "inventory", and "use". You can also ask "why", and bring up all commands available to you via "help".
Right now it's not clear how long the game's been available for, but it would appear u/attempt_number_1 is the first person to report the finding, and according to u/jeremyhoffman, the locations depicted in the game seem to correspond to "Google Mountain View buildings 45/47 on Charleston Road", giving rise to the theory that the programmer works from the Charleston campus.
To play yourself, open Google Chrome, and search for the term "text adventure". On the front landing page, type Ctrl+Shift+I - or CMD+option+I if you're using a Mac - and you'll find the game in the console. Just make sure you're using google.com; right now, it doesn't seem to be available on any of Google's local pages like co.uk.