At the time, it was only available to users of the canary and dev channels of the browser, but as of today, it is available to anyone who wants to try it.
The game will start even if you are not connected to the internet.
It is an amazing game for an easter egg, it has cute characters, many options, powerups and many ways to play. In addition to your keyboard, you can use a touch screen or a controller to play.
It is a cute easter egg that will distract her caution if you use the Microsoft browser. But don't overdo it if you work from home...