Riccardo Zacconi is the multimillionaire co-founder and former CEO of gaming business King, the company that was sold to Activision Blizzard for $5.9 billion in 2016.
Much of King's success was due to "Candy Crush Saga," currently the top grossing mobile iOS games app in the U.S., according to data from App Annie.
But in the early days, King struggled after Facebook first opened up to games developers, Zacconi told CNBC's "The Brave Ones."
"2009 is the year when (King rival) Zynga launched a game, which became incredibly popular, called 'Farmville'. And that's the year where Facebook also started growing massively. And so, between April of 2009, and a year later, Facebook impacted one of our biggest partners, Yahoo in an incredible way. We were the key partner of Yahoo and games," he said.
Zacconi described that period as "the most stressful time in my life," as he had to manage the expectations of investors and the board, as well as employees.
"Still we are profitable. Still we are OK, because we have loyal players who will stick with us," Zacconi would tell people. "But we're losing players and the revenues are slowly going down, and it's only a matter of time that we need to crack Facebook, or we will be out of business," he said.
The company launched "Candy Crush" on Facebook in 2012, a game designed by King co-founder Sebastian Knutsson. But a competing game, "Bubble Safari," by rival Zynga, was still getting more traction than "Candy Crush."
"But at some point after we launched, 'Candy Crush' actually flattened out on Facebook, because one of our biggest competitors, Zynga, who was much bigger than us launched ('Bubble Safari') a competitive game to one of our strongest games at the time, 'Bubble Witch', which was stronger than 'Candy Crush', and really hit us hard. For the first time, we saw our users going down, and our revenues going down," he said.
It wasn't until King launched "Candy Crush" on mobile that the number of users soared. King had designed the game to be accessible across multiple platforms, which meant that players could jump into the game seamlessly between their desktops and mobile devices. And it was this cross-platform strategy that fueled the game's success.
"We launched the (mobile) game in November 2012. And by the end of the month, the game … skyrocketed. I never experienced anything like that my whole life," Zacconi.
"We had a board meeting in October of 2012 where we defined the plan, and the budget for the entire following year, 2013. And by the end of November, we had already achieved the entire plan for the following year," Zacconi said.
Zacconi stepped down as CEO of King in May to become its chairman.