Facebook's ranking of the most popular games on the social network revealed that larger developers such as Walt Disney's Playdom, Zynga and Electronic Arts are stretching their lead over smaller start-ups.
Facebook apps has historically been seen as a fertile market for entrepreneurial companies to build a user base quickly. But Facebook's analysis of games with more than 100,000 monthly users found better-resourced firms were getting higher user-satisfaction scores as the market grew more professionalised.
"The barriers to entry have certainly risen in the past year," said Steve Bailey, games analyst at IHS Screen Digest, a consultancy. "It's a market that's achieved maturity very quickly. Competition is now at saturation and the cost of acquiring users is far greater than it used to be."
Zynga, which floated on the stock market this month, built its business on the back of Facebook's growth. The Californian company developed four of the top 10 most popular games of 2011, according to Facebook. Independent market tracker AppData ranks Zynga as the largest developer by monthly users, with 225m globally. Nearest rival Electronic Arts has 54m users, followed by Wooga, an independent firm, with 35m.
But industry observers were surprised that Facebook's data showed Playdom's Gardens of Time pipped Zynga's Cityville to the number one spot, as Disney's $400m acquisition of the social games developer started to bear fruit.
Electronic Arts' $400m acquisition of Playfish in 2009 has also proven a success, with its Sims Social taking second place in the Facebook rankings.
Scale is vital in the Facebook app market because it gives developers a springboard for new releases, creating a virtuous cycle that Zynga has exploited. But investors see opportunities for new entrants. In May, Caesars Entertainment, the casino operator behind Harrah's and Caesars Palace, was reported to have paid $80m-$90m for an initial 51 per cent stake in Playtika, maker of Slotomania-Slot Machines, the ninth-ranking Facebook game.
"By the third quarter of 2011, the level of investment in games was almost double 2010, and the level of M&A was more than double 2010," said Tim Merel, managing director of Digi-Capital, a technology-focused investment bank. "Whether 2012 or further out, we anticipate that both investment and M&A in online and mobile games should continue to accelerate."
Mr Merel and Mr Bailey both predict that the social games market will converge with mobile games in the next 18 months, as Facebook becomes hooked into more smartphones.