As of now, Android has a market share of 61.9% in the U.S. Internationally, this number is even higher: 82.7%. By developing on this platform, you are likely to reach out to a larger audience, increasing the potential for income. Additionally, Google Mobile Ads, with its ability to provide targeted ads from various ad networks based on demographics and location, is way powerful and wide reaching than iAd on iOS, there by increasing the chances of ad revenue. Android’s applications are written in Java programming language, a widely used popular modern language, requiring a smaller learning curve compared to Objective C on iOS.
Why 2D games?
3D games are significantly complex compared to 2D. From a programming perspective, 3D requires more math skills. Data structures are complex, animation is hard to program, and the volume of data is much higher, making memory management and app responsiveness a difficult task. Art work for 3D tends to be more complex and the set of skills required is wider. From a design perspective, it is difficult to author levels and level physics. Comparatively, you can develop in 2D much faster with little to no experience in game design.
Why Unity3D software?
Unity3D takes away most of the difficulties associated with a game design. It provides a built in physics engine, which otherwise would require a large amount of effort to develop. Unity3D also provides a rich and sophisticated animation system, with the ability to set up animations on a variety of objects, including humanoid characters. It also provides a built in AI capability for navigation and path finding.