As of this month, Epic Games’ Fortnite has been downloaded more than 40 million times. Even though this is a free game, this is still a very impressive growth. In case you haven’t seen the 1000 Snapchat stories, it seems like EVERYONE is playing this game. But why?

When Fortnite was first released, it was conceived as a sort of zombie tower defense game. This is now one of the two game modes called Saved The World. It consists of players hunting for resources and defending their base from the fierce undead attack. But it wasn’t until they introduced the Battle Royale game mode that the game took off. Battle Royale consists of 100 players being thrown from a flying battle bus onto a huge island with one simple goal: to be the last one standing. As everyone starts to battle each other, the area on the map that is called the "safe zone" begins to shrink. The area not in the safe zone is called the “storm”. This does damage players who remain in it.

The game might look an awful lot like PlayerUnknown’s Battlegrounds (a.k.a PUBG), but you’re wrong if you think they are the same. Fortnite: Battle Royale actually includes a building system. When you land on the map, you’re given a pickaxe. With that pickaxe, you can harvest things around you to such as wood, stone, and metal resources which can then be used to build small bases. These aren’t invincible though. As a matter of fact, almost everything on the map is destructible, making Fortnite a lot more chaotic and fun. Epic also releases limited time game modes, new towns, new guns and more.

Fortnite: Battle Royale is free to download and play on Xbox One, PS4 and PC.