Over the last couple of years since our Amazon Appstore launch, we’ve talked with many unique and inspiring developers. Along the way we’ve learned quite a bit and wanted to pass some of those learnings back to our developer community. So to that end, we are excited to continue our Developer Spotlight series. This series will highlight developers’ experiences building apps, ranging from what inspires them and how they’re delivering innovation to consumers to the results they’re achieving.

For today’s spotlight, we’re excited to chat with one of the co-founders of ZeptoLab, a global gaming company whose game Cut the Rope has been an instant success since its debut in October of 2010. The game remains a top app throughout mobile markets, browsers and desktops, and has been downloaded more than 400 million times to date.

Below is our interview with Zeptolab co-founder and CTO, Efim Voinov.

Why did you start Zeptolab?

Creating games was a hobby for my brother and me since early childhood. We’ve started with the games for ZX Spectrum in the early 90s, switched to PalmOS in the 2000s, and jumped into iOS and Android development since the first days of those platforms. At that time we already had experience in several gaming companies, and thought it was the right time to start something on our own. The new platforms offered exciting opportunities for independent developers, and we believed they shouldn’t be missed.

When did you start Android development for Cut the Rope?

The original version of Cut the Rope was released for iOS only, since there were only two of us developing full-time, and we had to concentrate on a single platform. After the game was out, we started to receive feedback from the players that they would like it on other platforms, and Android was the most requested one. Once the company had grown enough, we started developing it and about eight months after the release of the original we had the Android version. The version for Amazon Appstore was released at the same time, and required very little adaptation.

What changes did you need to build into the game to make it available for the Amazon Appstore?

Since we released Cut the Rope, we’ve created other titles, like Cut the Rope: Time Travel, Cut The Rope: Experiments, and Pudding Monsters. All of our titles are available in the Amazon Appstore. The process of porting the app for Amazon is very easy; we simply swap out billing API’s for the Amazon API for billing, which is something we do for all platforms we sell our app on. In addition, we are using GameCircle to handle leaderboards and achievements for games in the Amazon Appstore, which we have built in.

What’s it like to work with Amazon?

We think the Amazon API’s are very well thought through, the implementation is efficient and it’s easy to find information on how to use them. Having this ease of use is very important to us because we have lots of different versions of the games and really value the quick turnaround time to support games. In cases where we need more information the documentation level for Amazon API’s is very good and compared to others it’s in many cases above the competition. We don’t have to communicate with the Amazon team a lot in terms of understanding how to implement.

We also really appreciate your developer relations team. Having these relationships with the team helps us plan for the future, so we can plan for our business and consider the best way to implement new API’s and improvements into our games. The level of technical features being brought to market is impressive.

What are you looking at doing next with the Amazon Appstore?

In our current titles we are actively using IAP and this is proving to be quite successful for us in the Amazon Appstore. They currently bring us more than 40% of our revenue, and this figure is growing. In general, our cumulative income in the Amazon Appstore is doubling every year, and we are looking forward to increasing this trend in the future. With the latest release of the Mobile Associates API, we are looking at various opportunities to sell physical goods for our games.

Do you have any tips and tricks for developers building mobile games and applications?

One of the things that we learned is that it’s really important to minimize the routine tasks during development, and optimize the process as much as possible. That’s why we have invested quite a lot of time into our own framework, which includes different tools that automate various tasks. For example, we have an animation system, which allows us to automatically export animations created in the Adobe Flash directly to the game.

We also try to keep things as abstract as possible while designing a native OpenGL application for the Android platform. We try not to rely too heavily on a list of pre-defined resolutions, even if the list is extensive, because hardware specs are always changing. Instead, we try to invent a system for adopting current graphics to any imaginary screen proportion and only switch version for graphic assets depending on a real resolution. The one constant that does not change is the size of a user’s finger. We try to estimate an optimal physical size for a gesture and calculate using real measures like dpi and screen size in inches on every device.