Cute little discovery! So it might not be the most exciting game in the world but it's always amusing to discover little treats that the programmers deliberately left behind for people to find out
Someone just found an Easter egg in YouTube that allows you to play good ol' game of Snake!
ON Mac: Just hold down the left arrow. The up button is unnecessary.
ON PC: Just hit or hold down the left arrow.
You have to be on the actual fully loaded video page though - not the embedded or on the channel page.