A long-running battle between Apple Inc. and Google Inc. for mobile dominance is spreading to the most lucrative genre of apps: videogames.
The two Silicon Valley giants have been wooing game developers to ensure that top-tier game titles arrive first on devices powered by their respective operating systems, people familiar with the situation said.
In exchange, Apple and Google are offering to provide a promotional boost for these games by giving them premium placement on their app stores' home pages and features lists, these people said.
Last August, for the launch of "Plants Vs. Zombies 2," a highly anticipated sequel to a popular zombie-survival strategy game, publisher Electronic Arts Inc. struck a deal with Apple, which promoted the game prominently in its App Store, according to people familiar with the matter.
In exchange, one of these people said, EA agreed to give Apple about a two-month window of exclusivity for the title, which wasn't released on Google's Android software until October.
ZeptoLab's sequel to its popular puzzle game "Cut the Rope," introduced in December, reflected a similar pattern. The company and Apple agreed to about a three-month window of exclusivity for Apple's App Store, in exchange for the store prominently promoting the game, one person familiar with the matter said. ZeptoLab launched an Android version in late March.
Apple and Google representatives declined to discuss specifics of their exclusivity efforts. Exclusive titles are a common marketing strategy for videogame consoles, but are new to mobile apps.
Their rise marks an escalation in the battle for mobile-device customers, with Apple particularly determined to counter the rise of Google's free Android software.
Emily Greer, head of Kongregate, a gaming service owned by retailer GameStop Corp., likened the contest to an "arms race" for the best content.
"When people love a game, and it's not available on an alternate platform, they'll change platforms," she said. "The level of attachment a person has to a game can exceed almost anything."
Apple, which quickly became a leader in the smartphone market after introducing the iPhone in 2007, has been grappling with growing sales of Android-based phones by Samsung Electronics Co. and other manufacturers.
Nearly 80% of the one billion smartphones shipped around the world in 2013 used the Google-developed software, according to research firm IDC. At the same time, Apple's market share has dwindled to 15%.
Apple for years attracted most new apps first. Game makers say that was partly because it was easier to develop games for Apple's iOS software and that it ran on fewer devices. By contrast, there are many variants of Android, which runs on a wide range of smartphones and other devices.
But Android has gained ground in recent years, leveling the playing field between the two camps. Besides the attractions of Android's huge market share, tools for writing software have gotten easier to use.
Some $16 billion was spent on mobile apps last year, according to a joint study by research firms IHS and App Annie. Videogames accounted for more than 70% of the total, according to App Annie estimates.
"Videogames are critical applications," said Patrick Mork, a former director of global marketing for Google's app store and now chief executive of mobile- game company Unspoken Tales. "Not only is it where people are spending their time and money, they also showcase the power of computing on their devices."
Game developers, meanwhile, face increasing pressure to stand out from their rivals and persuade gamers to try their wares.
Prominent display in an app marketplace can produce as much as a tenfold spike in daily downloads, depending on the location of associated banner ads and how long a promotion runs, Mr. Mork said.
For Apple, the push to secure exclusive games challenges a long-standing policy of leaving decisions about which apps its App Store promotes to an "editorial team" that tests the software, without taking business considerations into account.
As Android's influence has grown, Apple's editorial team has been factoring in exclusivity to a greater degree after it deems an app to be attractive, according to people familiar with the process. The editorial team also will give greater consideration to titles recommended by its developer-relations staff, they said.
Apple doesn't offer money for game exclusives, only marketing or promotional assistance, these people said. It typically makes such offers after meetings in which game makers either discuss or demonstrate their coming titles.
The Electronic Arts and ZeptoLabs games were promoted in a large box at the top of the App Store's home page.
An Apple spokeswoman declined to comment, as did a spokesman for ZeptoLabs. An EA spokesman said the company "works closely with both Apple and Google."
Gonzague de Vallois, head of sales and marketing at French developer Gameloft, creator of the popular "Asphalt" racing-game series, said he and Apple had discussed swapping exclusivity for promotion, but Gameloft ultimately decided it would be better to launch an iOS and Android simultaneously. "We haven't found the case where it makes sense for us," he said.
Google has struck deals to help promote apps that integrate Android branding. In one example in March, Game Insight, a popular Russian app developer, says it offered discounts on items shaped like Android's robot mascot that were sold within a game. In return, Google agreed to feature the company's app in a specific section of its app store.
Amazon.com Inc., too, has gotten into the act. The online retailer has sought exclusivity deals with game developers as a way to boost the appeal of its Kindle family of Android devices.
Amazon is offering premium placement on its app store's home screen in exchanges for exclusivity, according to people familiar with the matter. "We work with many developers to bring their apps to the Amazon Appstore, some of which are exclusive to our store," said an Amazon spokeswoman.
Software exclusives appear to attract buyers to specific hardware products, particularly in the videogame industry. That inspired Microsoft Corp. to secure an agreement that "Titanfall," EA's new and well-regarded space-age shooting game, would be released only for Xbox consoles and personal computers this spring.
But Lewis Ward, an analyst at IDC, questioned whether exclusive titles have comparable impact on consumers' choices for tablets or smartphones.
"In terms of decision factors of why you buy the device you do, games are very low," he said.