King could easily have stayed private and milked this cash cow for many years to come. But that title's momentum atop the charts faded quickly, and sequels never measured up. Zynga tried to replicate lightning in a bottle by buying up other breakout games, spending around $200 million for the viral sensation Draw Something. Zynga, which built its fortunes around Facebook gaming and its infamous title, Farmville, has struggled to find another big hit and lost more than half its value since going public. The promise and peril of King's business is a common phenomenon in the gaming industry. If it's going to succeed as a public company, it will need to find a new source of momentum. The number of people who play Candy Crush, along with the sales and revenue it generates, has already begun to slow down and taper off. It's still a big win for the company's founders and employees, but the company has a tall order ahead.

But it fell short of that valuation with a poor early response from the market, with shares opening at $20.50 - beneath the offer price of $22.50 - and falling still lower to close down 15 percent by the end of day. King Digital Entertainment, maker of the wildly popular mobile game Candy Crush, went public this morning on the New York Stock Exchange after raising about $500 million in an IPO that valued the company at about $7.6 billion.

Why is candy crush so slow