The game's popular (and free-to-play) "Battle Royale" mode — where 100 players per game battle it out to the death with a variety of weapons and tools at their disposal — was played by more than 78 million people in August alone.
At one point in February 2018, "Fortnite" had over 3.4 million people playing the game online at once. The game has become something of a cultural phenomenon to the point that celebrities like the rapper Drake and singer Joe Jonas have been known to spend their time playing with everyday gamers. In June, Epic Games hosted a Fortnite Celebrity Pro-Am where 50 professional gamers will team with celebs like NBA star Paul George for a shot at $3 million in prize money.
Despite being free to play, "Fortnite" has already pulled in more than $1 billion in revenue, including an estimated $318 million in May, according to research firm SuperData, thanks to in-game purchases by players who spend money on things like new costumes and tricked-out tools (like a pickaxe outfitted with glow-sticks). The game is on pace to gross roughly $2 billion this year alone.
But "Fortnite's" huge success is a stark contrast to the first game that Sweeney developed for Potomac Computer Systems (the original name for the company that later became Epic Games) in 1991. Called "ZZT," customers purchased that game by mailing a check to Sweeney's parents' house in Maryland and waiting for him to mail a copy of the game back to them on a computer disk.
The PC game that gave players the tools to basically create their own customized video games within the game. Sweeney first started working on "ZZT" as a teenager; in fact, he'd been programming computer games as a hobby since he was 11 years old.
As a kid, Sweeney would play classic video games like Nintendo's "Super Mario Bros." partly just to figure out how they worked, so he could build his own. "I would play games long enough to discover what games were doing and how they were doing it. And then I'd spend the rest of my time building," Sweeney told gaming site Kotaku in 2011.
Sweeney decided to launch his own company after finding himself hating a "succession of jobs," he told the gaming site Gamasutra in 2009, including mowing lawns and making minimum wage (about $4 per hour at the time) working at a hardware store. "That really sucked," Sweeney said.
But, those early jobs also helped bring out Sweeney's entrepreneurial side. After borrowing a tractor from his dad, Sweeney told Kotaku, he'd charge half the price of established landscaping companies to mow lawns in his Maryland neighborhood, thus undercutting his competition while making about $25 an hour.
"That's when I came to a really clear realization that, by trying harder, and striving to find cool business opportunities, you could do far, far better than the wage earners," Sweeney said. "At that point it became really clear to me that there were big opportunities in the world."
Sweeney first started Potomac Computer Systems with a plan to focus on computer consulting and making online databases for customers, but he told Gamasutra he "didn't get anywhere with it." He kept the name even after he pivoted to video games, and spent nine months building "ZZT," simply because he already had "business cards with 'Potomac Computer Systems.'"
"I was working on it part time between mowing lawns in the summer and going to class in the school year," Sweeney said in 2009.