[Unlike the iOS platform, whose App Store is the only legitimate way to get commercially-released games into the hands of players, Google's Android platform allows for many different options -- and in this article, Gamasutra explores several of them to find out just what developers should know before selecting one.]

There are now more Android-enabled phones out there than iPhones. 400,000 new Android devices are activated each day. Yet iOS remains both a more lucrative and more popular market for game developers. We've all heard the reasons: Android users don't spend money on apps; the multitude of different devices and app stores makes for a fragmented marketplace.

But for all its problems, Android is still a huge market, and one that will likely only continue to grow... which makes it hard to ignore.

Comparing Apples and Androids

Even so, it's rare to find game developers creating titles exclusively for the platform. It's much more common to see developers that have had success on iOS or other platforms attempt to replicate that with on Android. The top-selling Android games tend to be familiar faces like Angry Birds or Fruit Ninja.

Infinite Dreams went down this route when it released ports of its hit iOS games Can Knockdown and Can Knockdown 2 on Android. Though the first game in the series is free to download, the sequel currently sells for $0.99. And while sales haven't been as strong for the port when compared to the original iPhone version, the studio still believes that the Android market is an important one.

"When you compare iOS sales to Android sales it's obvious that Android still has a long way to go," Infinite Dreams vice president Marek Wyszynski says. "Android devices sell in big numbers, but somehow iOS owners are more likely to be involved in purchasing applications. I believe this will change over time, and Android will catch up. That's why we want to support Android and release all of our products for this platform."

In fact, Infinite is going so far as to make multiplatform development a large part of its strategy. By using Unity 3D, Wyszynski says, it's relatively easy to create a game for both mobile platforms with a minimum of fuss. However, he admits, the large number of different Android-enabled devices out there does lead to some problems. That being said, upcoming titles like K-Rally 3D are being developed simultaneously for both platforms.

"We try to think about our games as multiplatform products as early as possible," he says. "Good design decisions plus the technology we are using [Unity 3D] makes it not very difficult to develop for both platforms at the same time."

And that seems to be a common belief amongst developers. While figuring out how to monetize games on Android is currently very difficult, the sheer size of the market makes it very attractive in spite of this.

That's why Get Set Games decided to port its popular freemium hit Mega Jump to the platform. Since the studio has just five employees, the port was handled by an outside company, found through the OpenFeint social gaming service. For Get Set, it wasn't just capturing a piece of what could potentially be a lucrative market, but also diversifying its portfolio that prompted the decision to port Mega Jump.

"From a business point of view, it's obvious that it's a massive market, and it's growing fast, growing faster than Apple," explains co-founder Matt Coombe. "So it made a lot of sense that we would want to be on more than one platform from a diversity point of view. Being on more than one platform means that if anything like this happens with Apple [referring to an issue with Mega Jump's thirteenth iOS update, which forced the studio to temporarily pull the game from the App Store] and your revenue goes down, then you have other streams of revenue."

As a free-to-play game, Mega Jump relies on in-app purchases to remain profitable, and as Get Set learned this can be an issue on Android. The multi-step, and frequently slow, process for purchasing virtual items in an app makes users less likely to actually go through with a purchase, which means much less revenue. Coombe describes it as "a real friction area on Android."

The Android version of the game only truly became financially viable once the studio implemented Tapjoy, an alternate payment service that allows users to earn virtual currency for free by installing apps.

"We certainly wouldn't have made our money back the way things were going with just in-app purchasing," says Coombe.

However, this too proved to be somewhat of an issue. The multiple app stores where users can buy Android games each have different rules, and Mega Jump was actually rejected from Amazon's newly launched store because of the inclusion of Tapjoy. Tapjoy directs users to a marketplace outside of Amazon's store, which, as it turns out, is a violation of Amazon's terms of service.

Having to deal with so many different app stores makes Android a much more complicated option compared to its competition.

"It doesn't work like a huge single market," says Coombe. "It works like a ton of little markets. It hasn't turned into a huge part of our revenue."

But, like Infinite Dreams, the initial difficulties with Android haven't dampened Get Set's belief that the platform will eventually become very important. To that end, the studio hired its fifth employee earlier this year who, in addition to managing the team's social strategy, also oversees the Android portion of the business, allowing the rest of the team to focus on the ongoing development of the iOS version, as well as other upcoming projects.

So while the monetary benefits may not have been all that great initially, Get Set still views its early experiences with Android as being very important.

"Getting our feet wet and understanding it better, being involved in it is really important," says Coombe. "And we're really happy to have done that and know what's going on."

Fighting the Friction

This issue with Android users' resistance to in-app purchasing makes services like Tapjoy even more important than on other platforms. An increasing number of mobile games are being released for free, and without in-app purchases new ways of making these games profitable are needed.

Currently, Tapjoy is available on both iOS and Android, and has over 9,000 games across its network and 200 million users. In addition to providing free virtual currency for users and advertising for games, the service also provides things like virtual currency hosting and analytics for developers.

According to Tapjoy's Matt McAllister, these services are especially important on Android. Users can still access the content, but without the friction inherent in actually making a purchase. This, he says, creates a win/win scenario in which the users get what they want for free without damaging the developer's ability to still earn money.

"We've seen that Android users are used to seeing great services for free, which is characteristic of what folks expect from Google," McAllister says. "We've definitely seen more users buying paid applications on iOS vs. Android, but with all the movement to freemium apps, the game is changing and we're excited to see it unfold as more and more titles take on a freemium business model on both platforms."

Tapjoy is currently working on a solution to the Amazon issue. It also has run into friction of its own on the iOS App Store, thanks to Apple deciding to limit the type of offers it provides. However, the company also plans to roll out additional services to make its platform more attractive to developers.

Diamonds in the Rough

Android's open nature also means that services are being created that really couldn't exist on a more closed system like iOS.

For example, after years of working in the PC gaming space, Exent recently launched a Netflix-style distribution platform for Android games called Gametanium. With it users pay a monthly fee, often bundled as part of their monthly carrier bill, and have unlimited access to a library of games.

It's a unique service that also has a unique payment structure, which actually rewards developers for how much time users spend with their games. Each minute of gameplay is logged and goes towards increasing the developer's share of the royalties. So the more minutes your game gets played, the more money you'll end up earning.

In theory, this system rewards developers who release better games, as users are more likely to replay games they enjoy. According Exent's director of content and programming Rick Marazzani, this system solves the two biggest issues with the Android market: monetization and discovery.

"We saw a lot of problems in the Android marketplace in merchandising, monetizing games," he explains. "Google... that's not their forte, monetizing and charging for content. They're pretty good at ads and getting the right answer in front of you, and monetizing it via eyeballs.

"But as far running a storefront with discovery and marketing and promotions, all of the things that we've done for years [on PC], for our operator partners, we brought all that to bear for our own solution on discovering apps, for promoting apps, merchandising them, and then monetizing them via a subscription, which is either paid for directly by the user or integrated into their phone bill."

Gametanium also hopes to differentiate itself through quality. Marazzani describes the current crop of Android games as being "99.9 percent... complete garbage." And to that end Exent is being very selective with deciding which games end up on the service. It soft-launched with around 100 games and will "grow as quickly as good games come out."

It's a mindset similar to that of HyperBees, an Android-centric mobile games publisher. Launched in late 2009, the London-based publisher helped release its first game in February 2010 and since then has gone on to publish a number of high selling games.

HyperBees published games have seen more than four million downloads in total, and titles like SpeedX 3D and Impossible Level Game both managed to crack the top 10 paid games chart on the Android Market, reaching as high as the number five spot. In order to ensure that the games it publishes are of the highest quality, HyperBees actually starts working with developers very early on in the creation process.

"When it comes to the development process, we prefer to be involved as early as possible, starting from the game's concept, through UX to monetization," says co-founder Tom Mleko. "In some cases, for example with ShakyTower [an upcoming title], we go through more than 20 iterations. I suppose working with HyperBees might be tough for some. There are some approaches we will never agree to, like releasing games prematurely. But other than that I believe we are reasonable people. We do not have a problem with killing our ideas if they don't hold water."

Like Exent, Hyperbees is hoping that this quality-centric focus will help alleviate the new app discovery issue. By releasing only games of a certain level of quality, users will then begin to associate the HyperBees name with games that they enjoy.

But on a platform as crowded as Android, simply being a good game isn't always enough. And that's where the publisher comes into the picture.

"The reality is that with so many games on the market if you want to earn money, your app needs to be not only very good but also well marketed," explains Mleko. "That is not so easily done without at least some experience or knowledge about how to monetize.

"The HyperBees brand also plays a role: players know it, bloggers and the community know it. Okay, we're not Rovio, but I think we're doing fine."

While there are plenty of concerns surrounding the platform, there are also two factors that make Android an extremely attractive space: its openness and its ever increasing size. It's why developers like Get Set and Infinite Dreams have ported games to Android and its why companies like Tapjoy, HyperBees, and Exent are looking at new ways to monetize and promote apps.

Enter Amazon

But these factors are also attracting larger names from outside of the traditional gaming, or even mobile, space. Names like Amazon. The largest online retailer in North America launched its own Android app store back in March, complete with unique aspects like an in-browser "test drive" feature that allows users to play around with an app on their computer before making a purchase.

Though the IGDA has expressed concerns over Amazon's terms of service, specifically with regards to pricing, the mobile marketplace has managed to attract some big names in the gaming space.

The app store launched with the at-the-time brand new Angry Birds Rio as the initial "free app of the day," and more recently PopCap announced that its first two Android games, Chuzzle and Plants vs Zombies, would be timed exclusives, launching first on Amazon's store before eventually being released on Google's marketplace.

It may seem like an odd fit -- a giant retailer and a mobile app store -- but Amazon and Android actually seem to work together surprisingly well.

"We've spent years developing innovative features that help customers find and discover relevant products from our vast selection, and we're excited to be able to apply those capabilities to the apps market segment," says Amazon's Aaron Rubenson.

"An app store is a logical next step for Amazon. We take mobile shopping very seriously and across the company, we are working hard to make great products and services available on mobile devices."

While Amazon's app store features a significantly smaller number of apps compared to the Android Market, the company's huge customer based and proven marketing and merchandising techniques -- such as very effective personalized recommendation features -- that make it such an attractive place to release a game. It's also possibly the only place where you can both buy a new phone and the apps to go along with it.

Rubenson says the company's goal is to "[make] it as simple as possible for customers to purchase developers' apps both online and on their mobile devices."

Angry Birds Rio

Looking ahead

Overall, Android is an incredibly interesting place right now. Though the platform has been around for three years, in many ways it's still maturing. It's a fragmented market, both in terms of the number of places you can buy apps, as well as the wide range of hardware available to run them on. This complicates everything from the actual development process to marketing and selling a game.

Though this article looks at a number of solutions, there are many more -- both those that are already launched, and upcoming ones, such as Ngmoco's Mobage service, which on Android will bundle apps together as an interactive "channel" for players.

But that hasn't stopped developers from flocking to the platform. Because for all of its issues and the difficulties in actually earning money with Android games, there's also a sense that as the platform continues to grow and expand things will only get better.

"Until four to six months ago, Android was playing catch-up with iOS but now I am certain that it will be the more attractive platform eventually," says Mleko.