When comparing Rainbow vs Wave, the Slant community recommends Wave for most people. In the question“What are the best 2D game engines?” Wave is ranked 33rd while Rainbow is ranked 79th. The most important reason people chose Wave is:
In addition to online [API documentation](http://waveengine.net/Engine/Documentation), the Wave Engine team provides [tutorials](http://www.indiedb.com/engines/wave-engine/tutorials) via IndieDB, plus [sample projects](https://github.com/WaveEngine/Samples) and "[QuickStarters](https://github.com/WaveEngine/QuickStarters)" via GitHub.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Open source
Distributed under the MIT License.
Pro Written in modern C++, is scriptable in Lua
Pro Cross-platform
With support for Android, iOS, Linux, Mac OS X and Windows.
Pro Optional FMOD audio engine
Pro Supports Spine
Pro Physics
Box2D integrated with Lua bindings.
Pro Extensive learning material
In addition to online API documentation, the Wave Engine team provides tutorials via IndieDB, plus sample projects and "QuickStarters" via GitHub.
Pro Supports coding in C#, F# and Visual Basic
Wave Engine explicitly supports all three core .Net Platform languages.
Pro Oculus Rift support
The Wave Engine team provides an official, open-source Oculus Rift extension via GitHub.
Pro Many components are open source
Several core components and official extensions of the Wave Engine are publicly hosted on GitHub.
Cons
Con Not as feature-rich as other engines
Con Small community
Being fairly new on the scene, there aren't much of a community to speak of.
Con Mandatory splash screen
Games and applications made with Wave Engine must display a splash screen advertising it. No splash-free license option is available.
Con Not many tutorials available
Con Outdated UI
The UI looks like it is from Windows XP days. A refresh is much needed.