Cocos2d-x and Cocos Creator vs Unity

25% of iPhone games are made using Cocos2d-x.

This means you will not be alone in development, and will have access to a large community. You'll know you are developing for an engine that works.

Documentation includes a programming guide, API reference, video tutorials and massive reference test code project showing all functions and giving working code to the user.

A new feature since Cocos2d-x v3.1 is support for 3D models (in your 2D game), not only this but support for skeleton animations is included too! This awesome feature allows for impressive characters in your game along with easier, more fluid and realistic animations.

It supports Lua and Javascript with full feature support.
Especially with Cocos2d-JS you can develop games cross web and native, and the native solution have great performance with JS Bindings, much better than hybrid solution.

Cocos2d-x forums are active.

Cocos2d-x is not only open source but also supported by Chukong Technologies of China and USA.

Regularly updated and adding support for the latest technologies. 2014 has already seen the release of Version 3, a new Cocos Studio development toolkit (optional) and support for new technologies like skeleton animation systems Spine and Adobe DragonBone.

Cocos2d-x is C++ based engine and it has CPU advantages for most platforms because of that. It uses polygonal mesh methods for sprite rendering for using GPU advantages. (You also use quad methods for benefit CPU).

Because it is based on Pyglet.

On top of supporting pretty much all existing platforms (except consoles), Cocos Creator (Cocos's IDE) allows you to write 1 code that runs on Android, iOS, Windows, MacOS and HTML5 (not Linux though).

Through the use of SDKBox you can easily integrate 3rd party SDKs and plugins for each version of Cocos2D (Lua, C++ or JavaScript), you just choose the SDKs to integrate and SDKBox will do the rest.

For example, if you want to add a rating plugin, you use sdkbox::PluginReview::init(); and if you want to add the Vundle Ad Network SDK, you use the one packaged in SDKBox SDKBOX sdkbox::PluginVungle::init();.

It has a built-in Python interpreter that allows for easy debugging.

Cocos Creator (Cocos' IDE) comes with scene editing, UI editor, animations & particle editors and whatnot. It's also easy to use and pretty intuitive if you read the official documentation & tutorials. Way way better than the old CocoStudio.

Hundreds of video tutorials available.

Unity is bolstered by a huge, helpful community via its official forums, wiki, Unity Answers, and Unity Asset Store; plus the most-subscribed subreddit of any game engine.

Unity offers over 20 platforms for publishing including mobile, console, web, VR, and more.

Not tailored for specific types of games (like Unreal...), so it won't get in your way if you want to make something unique.

Overall, a coherent engine with a rational approach. People who complain a lot about being forced to hack around it usually do not read the docs, like the one that describes orders of execution, or specific functions hooks and such. Some like to say it lacks raw power where people who are used to standard optimizations have no problem. For example It is not uncommon to encounter users who complain about low FPS but forgot to activate occlusion, flag static elements, activate animations culling, and so on. As for complaints about C#, people who are transitioning from C++ were already bad at C++ before being bad at C#. They often come from the PC world where the sheer power of today's machines is very forgiving compared to the platforms we had to develop for in the 80s~90s. One of their errors is for example to never read this doc.

Unity runs very smoothly even on systems that are considered "weak" by today's standards.

For those developers who can't afford an artist, or aren't skilled enough to create their own art, Unity features an Asset Store full of a wide variety of free and paid assets that can be easily added to a game. The Asset Store has more than just music and art. It also has code and modules that can be added to games including unique lighting or GUI systems. It also has powerful asset management and attribute inspection.

You can use any C# IDE for it, but the ones tested which have Unity integration are:

• Microsoft Visual Studio
• MonoDevelop
• Visual Studio Code (much faster than VS, but a bit harder to set up for Unity development)
• JetBrains Rider (very fast, has lots of functionality and best Unity integration, but it is not free)

Unity provides a great state machine animation system called Mechanim allowing to separate animation from the model and assign the same animoations to different models.

The built in standard shader in Unity 5 is incredibly optimized and supports PBS/PBR.

Unity's modular system and usability allows for quickly developing a prototype of an idea. It has features like drag & drop editing, shaders, animation and other systems already in place to allow diving right into developing a game.

The way the editor is structured, by setting scripts on objects, and the use of a high-level language, C#, makes it easy to learn.

Unity is a proven game engine. It is used by a wide range of developers - from small indies to triple-A companies such as Microsoft, Paradox, Square Enix and Sega.

Unity3D provides an exhaustive documentation where everything is given a full description supplied by a number of examples as well as video and text tutorials and live training sessions to understand the ins and outs of the engine. In addition there's an ever-growing community that can offer advice to help resolve any situations that may arise.

Along with the official Unity resources, there are many high quality (and often free) third party tutorials available.

The editor GUI is very powerful and intuitive. It allows pausing gameplay and manipulating the scene at any time as well as progress gameplay frame by frame. It also has powerful asset management and attribute inspection.

This allows it to be more powerful than other, simpler drag-and-drop engines such as Game Maker Studio, although it can take a bit more experience to learn the workflow.

As long as the company makes $100k or less, Unity's free version can be used to release games without purchasing the pro version.

With Unity knowledge of just one engine is needed to be able to create both 2D and 3D games.

Great Community support through Forums and Unity Answers.

There's an Asset Store, providing free and paid assets (including components). It also has powerful asset management and attribute inspection.