Cookie Clicker is a free idle game. The goal of the game is to make as many cookies as you can. You do this by clicking on the Big Cookie and buying buildings that make cookies. There is no end to the game, but some people think that getting all of the achievements is a way to "finish" the game.

At the beginning of cookie clicker game, the player has no cookies. The player can click on the Big Cookie on the left side of the screen, which makes one cookie at first. When a player has 15 cookies, they can buy a Cursor, which automatically clicks every 10 seconds. The player can then keep making cookies until they buy grandmas, farms, mines, and so on. At first, golden cookies may show up every 7 minutes or so, which can help boost Cookies per Second by a lot for a short time. Upgrades can be bought to make buildings make more cookies or just to make more cookies per second.

After making 1 billion cookies, the player can start making sugar lumps, which are a secondary currency used to level up buildings and slightly boost production. Some buildings, like Farms or Banks, have minigames that you can play when you level them up. Some minigames, like the Garden and the Stock Market, can be used to help increase CpS, and they also have their own upgrades and achievements.

Later in Cookie clicker game, the player can choose to start the Grandmapocalypse. This happens when the Bingo Centre upgrade is bought, which costs 1 quadrillion cookies. Because of this event, the game's grandmas turn into weird, fleshy creatures. When you start the grandmapocalypse, wrinklers start to spawn. They lower CpS, but when you pop them, you get more cookies than you lose. Wrath Cookies, which are usually bad, like cutting cookie production in half, have also turned into Golden Cookies.

After the player has made a certain number of cookies, they start making heavenly chips, which can be used when the player ascends. Ascending lets the player buy heavenly upgrades, like a cookie dragon or an upgrade that lets them change the seasons whenever they want. It also gives a flat CpS boost based on how many heavenly chips the player had when they ascended. Ascending also gives the player access to challenge modes like Born Again, which is like starting over from day 1. The ascension system makes the game pretty much playable forever.

The player can keep playing until they have a huge number of cookies, like tredecillions or even vigintillions.