Michael Ritter, Vice President Licensing & Distribution at Social Gaming Network, is our guest blogger for this post.  SGN connects people around the world through great games, including Skies of Glory, Fluff Friend Rescue, Warp Rush, Bird's the Word, and Night of the Living Dead Defense.

We decided to participate in the Amazon Appstore In-App Purchasing beta program because Amazon is a ubiquitous and trusted ecommerce platform with disruptive devices, so we felt it was a perfect storm of opportunity.   Amazon's in-app purchasing solution created a great way for us to reduce friction and drive more revenue from our games, as tens of millions of people already have made purchases with Amazon.  Specifically, the Kindle Fire’s integrated storefront and marketplace work seamlessly and help drive mobile game distribution.  Through in-app purchases we are able to add additional content to our games, which help deepen the player’s experience and increase their enjoyment.  

With our games we have tried a mix of revenue models, including paid, paid with in-app purchase, and free with in-app purchases.  Our strategy largely depends on the type of game and expected game play behavior.  In our Amazon games, the model revolves around the use of in-app purchases of virtual goods, although we are starting to experiment with ad-based games whereby users will have the ability to purchase the option to disable ads.  We feel the freemium strategy coupled with in-app purchases provides the greatest ability to delivery quality games to a large audience, while also providing free content for casual players and the ability to upgrade for those players looking for a richer experience.

From the consumer’s point of view, Amazon has done an exceptional job creating a natural and seamless purchasing process that allow users to easily make a purchase and continue playing the game. From a developer’s point of view, we found Amazon’s technical support team to be exceptional. They were attentive, helpful and very responsive to supporting and walking us through the installation process.  

Overall, I’d say that offering IAP in your games/apps is a great way to drive revenue as well as provide enhanced content for users to enjoy.   The Amazon Appstore SDK and In-App Purchasing APIs are well worth installing, whether your game is paid or free.

What is code obfuscation?

If you are ready to submit your app to the Amazon Appstore for Android, you might consider obfuscating your code. Obfuscating your code modifies your source and machine code to be difficult for a human to understand if your app gets decompiled. If you are concerned about your app being reverse engineered, using a tool to obfuscate your code can help a great deal.

Caveat

Not all of your source can be obfuscated, however. If you are implementing In-App Purchasing for your app, the Amazon Appstore relies on certain methods being available to call and provide you with information about a purchase request. If these methods get obfuscated and renamed, the Appstore will not be able to send information to your app. This post is a brief walkthrough on adding code obfuscation to your project.

Proguard

For android apps, Proguard is a code obfuscation tool that is provided to you once you download the Android SDK. The program shrinks and obfuscates your source code.

Setting Up Code Obfuscation for your Project

Prerequisites

This walkthrough assumes you have the Android SDK and Amazon In-App Purchasing API installed and your project already completed.

For help on installing the Android SDK, please refer to their website at http://www.developer.android.com/sdk/installing.html. Download the Amazon In-App Purchasing API by going to http://developer.amazon.com/

Enabling Proguard for your App

To enable Proguard for your Android app, refer to the following documentation from the Android SDK: http://developer.android.com/guide/developing/tools/proguard.html

Edit the build.properties file inside of your project, and add the following line (if you don’t have this file in your project directory, make one):

 ‘Keeping’ the In-App Framework Intact

When incorporating the in-app framework into your library, you will need to specify classes to ‘keep’ and not obfuscate. Add the following lines anywhere in your proguard.cfg file.

Finalizing and Releasing Your App

Now that you’ve fully set up your proguard.cfg and build.properties file, you can run Proguard through the ant  build script for your project.

Obfuscation with another Program

If you are using another program for code obfuscation, to ensure that in-app functionality is preserved, make sure your program does not obfuscate any class under the com.amazon.* namespace, including method names and identifiers. Your obfuscation program must also preserve annotations.

Conclusion and Additional Resources

The code in this article serves as a walkthrough for enabling and using Proguard for release candidates of your app. Sample apps that include the code from this article are provided in the In-App Purchasing API. Again, you can download the SDK by logging into http://developer.amazon.com/

G5 Entertainment participated in Amazon Appstore for Android’s in-app purchasing (IAP) beta program because they had successfully launched over 100 games with in-app purchasing on other devices.  Larissa McCleary, Director of Marketing at G5 Entertainment writes, “We found that by offering a product with IAP, rather than a traditional "lite" or "full" set of offerings, our conversion rates went up as did our revenue on a per title basis. Although our experience on Amazon has always been great, we are thrilled now that IAP is available. This will allow us to continue our business model, but also to allow other developers to partake as well. Eventually, if more and more developers participate, we think we will experience even higher conversion rates, since players will be more familiar with what IAP is and how it functions, making the play experience even more engaging.”

G5 Entertainment takes the approach that if the game is interesting, customers will be more engaged. The maker of popular games such as Virtual City Playground and Mahjong Artifacts, McCleary tells us, “Our basic strategy has been to make the games as fun as possible. We are working hard to optimize and improve our features on an on-going basis.” How do they decide what will be fun for players? Playing the games themselves, focus testing, and team brainstorms have all led to added content.  However, McCleary notes, “In the end we decided that we should let players decide what they want, by giving them as many in-app options as possible.”

The G5 team reported that overall, the integration was quick and simple. McCleary says, “The code was ready in one day, and metadata was entered quickly too.” Comparing their experience to past integrations, the Amazon Appstore compared favorably. “It’s definitely easier to integrate the Amazon IAP APIs than other IAP solutions we have implemented,” notes McCleary.

During the beta program, G5 found their main hiccup in the testing process. G5’s QA team provided feedback that helped the Amazon Appstore improve the testing process by introducing the SDK Tester. The SDK Tester allows a developer to validate common path and edge case scenarios in their app, all without uploading or configuring anything in the Amazon Developer Portal. This approach reduces the friction a developer faces when testing their apps, and allows for rapid testing across any device that supports the Amazon Appstore. Still, the IAP API was well worth integrating for G5, and the G5 team recommends “reading the documents available on Amazon’s Developer Portal and keeping your code simple.”

About G5 Entertainment AB

G5 Entertainment AB is a developer and publisher of high quality downloadable games.  G5 started as the leading mobile game development studio working for Electronic Arts and Disney. In 2009 G5 changed the business model to become a publisher of original games developed by G5 and over 30 partner studios in Eastern and Western Europe and the U.S.  G5 owns a number of successful game franchises, including Virtual City Playground and Mahjongg Artifacts.