"Fortnite" maker Epic Games has found a groove with its "battle royale" title in which scores of players fight against each other to be the last one standing in a post-apocalyptic world.

"Fortnite" was the focus of a pro-am tournament which packed a Los Angeles stadium during the annual E3 video game extravaganza and Epic Games has put up $100 million in prize money for competitions.

Reasons for the popularity of "Fortnite" include that it can be played for free on a range of devices including smartphones, personal computers and consoles. Nintendo added "Fortnite" to its Switch consoles this week.

"Battle royale is a proven and popular game style," Twitch eSports program head Justin Dellario told AFP.

"Fortnite" is the most popular game now on Amazon-owned Twitch, with more than six billion minutes of play in April alone, according to Dellario.

Hip-hop superstar Drake set a streaming record at Twitch in March drawing 628,000 viewers for a live stream of him battling for survival in the shoot-'em'-up adventure with players including Tyler "Ninja" Blevins, one of the emerging stars of the sector.

"Fortnite" became an eSports phenomena after the release late last year of a free "Battle Royale" mode that lets up to 100 players vie to be the last character standing on ever-shrinking terrain.

Read also: Ubisoft sees blockbusters shaped by fans and stars

- Players in the spotlight -

"Fortnite" was crafted to be easy to jump into and fun including goofy stunts, for example, such as riding rockets or shopping carts, according to Celia Hodent, who worked on user experience at Epic Games before leaving late last year.

"There is no recipe for making for sure a game is a huge hit, but now you have specific ingredients you use," Hodent, author of the book "The Gamer's Brain," told AFP. 

"What you are talking about is more a social phenomenon; when something is very popular then more people want to play it."

The three-day E3 event, once restricted to members of the multi-billion-dollar video game industry, was open to gamers for the second year in a row with 15,000 tickets sold.

Throughout an E3 gathering rich with eye-popping game software, players themselves were in the spotlight. 

Live game action and pithy commentary were streamed online television studio-style by platforms such as Twitch, YouTube, Facebook and Mixer.

"Game publishers understand their community is fundamental and allow the players to contribute to the games themselves," Facebook director of console and online gaming Franco De Cesare told AFP.

French video game giant Ubisoft announced at E3 that it is teaming up with a firm founded by actor Joseph Gordon-Levitt to crowd source material for a forthcoming title.

Ubisoft has long tapped into feedback from players while designing games, but the latest step will allow some to make content woven into scenes.

An invitation to collaborate went live on the website of Gordon-Levitt's Hit Record, with the first project being to make music that one might hear on a space pirate radio station in Ubisoft's "Beyond Good and Evil 2," a science fiction shooter crafted to be a space opera.

"These growing communities of players are already present," Ubisoft chief executive Yves Guillemot said.

"Hundreds of millions of people are part of eSports; build shared maps block by block, or battle for victory in online arenas."

A  coming sequel to the blockbuster "Fallout" franchise will be an open world hosted online and populated by other players instead of computer generated characters, Bethesda Game Studios director Todd Howard said at E3.

In the game "each of those characters is a real person," Howard said.