The makers of Candy Crush Saga, King, want to cash in for an IPO on the New York Stock Exchange, according to a filing the company recently submitted. But despite having a blockbuster hit game, King has a long saga ahead of it, if it doesn't want to get crushed in the market.

Candy Crush Saga -- a multilevel matching puzzle game -- is one of the most addictive mobile apps for iPhone and Android on the planet. Forget Flappy Bird; Candy Crush, which came out in 2012, used its easy-to-play nature and addictive learning curve to become the most popular app on Facebook (surpassing the FarmVille franchise) and one of the most downloaded free apps on iOS and Android in 2013.

So now King, the U.K.-based makers behind Candy Crush, have traveled across the pond to New York, where they filed for an estimated $500 million initial public offering (IPO) on the New York Stock Exchange this week, under the appropriately audacious ticker symbol KING.

While the company hasn't decided on a price for the IPO or a stock market value, according to the Wall Street Journal, financial details might put the company's value as high as $8 billion to $10 billion, though other analysts' estimates have it closer to $5 billion.

Taking any estimate, that's a huge amount of value to ascribe to King -- putting the mobile app developer in the same ballpark as giants like Activision Blizzard Inc. and Electronic Arts, if not in the same league.

But we've seen this kind of thing happen before, with the Zynga IPO in 2011. Zynga, which was riding on its similarly booming success of FarmVille at the time, opened for public trading on the Nasdaq Stock Market at $11 per share with a valuation of about $6 billion, but fizzled, its shares falling below the IPO price within the first 10 minutes of trading. Now Zynga is at about 50 percent of its IPO, having failed to replicate FarmVille's success and posting losses for the last three years.

King's filing shows that the company generated about $1.8 billion in revenue in 2013, but over three quarters of that profit came from Candy Crush alone, and most of that coming from the tiny percentage of "freemium" users who choose to buy upgrades within the game. King's growth has already slowed in the last quarter it reported.

King is at least addressing the "eggs in one basket" Candy Crush problem in its SEC filings, saying, "If the gross bookings of our top games, including Candy Crush Saga, are lower than anticipated and we are unable to broaden our portfolio of games or increase gross bookings from those games, we won't be able to maintain or grow our revenue, and our financial results could be adversely affected."

The fleeting boom of Flappy Bird, before its creator decided to take the game down, shows how quickly mobile game popularity can shift from a well-known giant like Candy Crush to a complete unknown. Much like the world of pop music, it's much easier for mobile game creators to have a "one hit wonder" than to build a long-lasting legacy of repeat success. To please investors, King has to become more like Madonna than Lou Bega.