Cookie clicker is a game where the player clicks on a giant cookie to earn money and then spends that money on upgrades to expand the business
There are multiple reasons as to why Cookie Clicker has gone viral. One of the main reasons is that there are no real goals in the game, and it's also one of those games where you can play for hours and not really realize what's going on.
The game starts off with one cookie and let’s you buy upgrades with your profit (money earned from clicking). Some of the upgrades will make cookies last longer, give more cookies per click, increase time between clicking, or even give you more clicks per second. The upgrades may seem cheap at first but they cost exponentially more as the game goes on.