With mobile phones becoming the most popular way for users to access the Internet in China - and Internet users there reaching 538 million at the end of June - China's booming mobile game business has become a substantial attraction to Western developers.

But Hans Kim, vice-president of business development and legal at Chinese social network site RenRen Games, said it's not that easy for Western game developers to get their titles into China.

"The Chinese market is very challenging," Kim said at the recent GamesBeat 2013 conference in Redwood City, California. "There are hundreds of app stores that you need to get mass distribution. There are all different channels, and they all have their hand out to get a cut, they all want a percentage."

Kim said when a Western game tries to get brought into China, his Chinese team usually would ask, "Is this going to monetize?"

In a country where users are used to the free-to-play model, gamers need to consider new strategies.

"How are we going to bring the games to China and how are we going to bring Chinese games to the West, I think we all have a lot of to learn," he said.

China's mobile game market made a quantum leap in 2013. It was expected that revenues from mobile game would reach 9.19 billion yuan ($1.5 billion), up 371.1 percent compared with 2012, iResearch said.

With increasing ownership of smartphone and mobile game players, and the development of the industry chain, including major overseas developers, publishers and platforms, mobile game revenues should sustain 100 percent growth to 17.85 billion yuan in 2014.

With such rapid development comes fiercer and fiercer competition.

"Even at Renren social network, we have huge competition with huge players in the China market," said Kim, giving Tencent's WeChat as an example.

"My advice is don't compete with dominant local competitors, work with them," he added.

China moved up two spots to become the third-highest grossing country on the iOS App Store. This move in the revenue rankings made the US, China, and Japan the top three countries by both downloads and revenue on the iOS App Store in the third quarter of 2013, a new report from research firm App Annie shows.

John Goodale, vice-president of Asia at Unity, believes even it is quite challenging to tap into the Chinese market, the mobile opportunity in China is really there and it is an exciting time to be looking at China.

"Particularly in the mobile spaces, the gaming industry in China is really in its infancy," Goodale said. "The growth potential for mobile gaming in China is really just getting started, it's a very exciting opportunity."

Globally, Goodale believes there are three key factors for a successful game: easy to learn, fun to play, and hard to master.

However, he noted there is a fourth factor that is critical for success in China, which is innovation. "You have to be continually changing and continually updating your game, because when you launch a game, it is going to be copied next day," he said.

Renren, often called China's Facebook, has set up Renren Games USA in Silicon Valley to deliver high-quality games to the North American market. Kim said the company is not rushing into the US game market but rather "looking at developing games that are suitable for both the China and US markets".

Another mission for Renren US is the talent hunt. "We look for talent worldwide, so any talented developer in the world should talk to us," Kim said. "We are looking for the highest quality content that is actually suitable for both the US and Chinese market."