Felgo (formerly V-Play) vs Starling

Qt-Creator IDE with Code Completion, Debugging and Profiling, integrated Quick Help, Version Control and more.

Felgo is among the easiest cross-platform tools to use according to a survey done by research2guidance.

With the Level Editor components, you can let your players share their levels with the whole game community which is cool because you don't need to create new levels on your own, but the community helps you with it. There are other community features like rewards for good level creators that helps getting more downloads.

Leaderboards, Achievements, Challenges are available across platform, even on Desktop. You can also use Cloud Syncinc of your game data that makes it easy to start a game for example on iPhone and then continue on a Nexus Tablet or the other way around.

It is also convenient because sharing to all kind of game services & networks like Facebook & Game Center is possible with a single API call. Custom hosting of Game Network servers is also possible if you want to keep the player data.

Although game logic is provided in JavaScript by you, performance-critical parts of the engine like OpenGL ES rendering or particle effects are implemented in rock-solid C++, providing the ultimate performance your game deserves.

Advanced Gaming Components for handling multiple display resolutions & aspect ratios, animations, particles, physics, multi-touch, gestures, path finding and more.

No need for native SDKs, Build in and Install from Cloud with the Felgo Build Server.

Cut your development time in half. Using the QML language allows for some powerful features that cut code lines and time. Another helpful feature that can help in this area is that there are more than 50 game demos of all genres that come with full source code, meaning one can easily check to see how something was done.

Felgo has friendly forums where core developers participate as well as fast & helpful email support.

The Qt framework is a great and mature framework on its own. Using Qt as a game engine base is a smart idea.

You can use ready-made components to balance any of your game properties at runtime, so also on mobile devices which is great for adjusting forces or input parameters.

Helps get started and improve with lots of tutorials, demo games, examples.

In-app purchases, game and social network integration (such as Game Center and Facebook), ads (with Chartboost and AdMob) and analytics (such as Flurry) are all available across platforms.

Every 2-4 weeks new updates provide additional features and fixes based on what users wanted the most.

You can even monetize these user-generated levels with in-app purchases with the Felgo Level Store component if you like.

Starling is just 12k lines of code and doesn't try to do everything — but what it does, as efficient as possible.

With Feathers, you can easily add great user interfaces to your games — or even create business apps with Starling.

Starling is available for free with code available on GitHub.

Forum is always active with knowledgeable developers and with lot of inside info, and post mortems.

With UI, you can design it in Flash Professional (powerful 2D editor), export to swf file, use GAF convert swf file to gaf file, finnally, load gaf file to Starling. GAF can convert a lot of file swf to one atlas. Alway use same resource in design files (fla) to optimize atlas size, avoid duplicate asset in atlas.

You can use flash to create animation for starling.

Let the GPU do the rendering, the CPU has more important tasks to do.

It can be exported to web flash player, iOS, Android, Windows, and OS X

Using AIR's native extensions any native code that can be written can be run and used by the game engine.

New features are added regularly.

Starling can run more animated display objects than Unity2D and many others frameworks at 60 fps.