Epic Games' Fortnite has consistently been one of the most popular video games in the world since its launch last year. Over 78 million gamers were playing Fortnite in August, according to Epic Games, and Newzoo ranks it as the second most popular core PC game in the world.Fortnite is a survival game with two main game modes: Save the World, a cooperative shooter in which players work together to fend off monsters and defend objects with fortifications; and Battle Royale, where up to 100 players battle to be the last person standing.