When comparing Genome2D vs SFML, the Slant community recommends SFML for most people. In the question“What are the best 2D game engines?” SFML is ranked 35th while Genome2D is ranked 47th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Lightning fast
It's the fastest gpu-based framework out there for flash. It's beautifully optimised. It has very low rendering latency, low level OpenGL calls that other tech simply cannot do (ie Unity) due to Stage3D, and thus can render a lot more data quicker
Pro Cross-platform mobile, desktop and web
Supports Windows, Mac OS X, Linux, iOS, Android, Web and native Flash.
And with the HTML5 export, it also potentially supports development for the Wii U :)
Pro Haxe!
Haxe is a strictly typed programming language that saves development time but still compiles high performance executables, and can build for tons of different platforms (flash, c++, html5, java, c#, etc.)
Pro Access to direct draw features
Has access to direct draw features so you can make you own rendering structures (scene graphs etc).
Pro Automatic dynamic batching
Automatically batch geometries with dynamic batching techniques (by using constant buffers).
Pro Component based architecture
Pro Very efficient and usable
Pro Zlib/PNG license
In short, SFML is free for any use (commercial or personal, proprietary or open-source). You can use SFML in your project without any restriction. You can even omit to mention that you use SFML -- although it would be appreciated.
Pro Can be combined with OpenGL
If you hate something about the way SFML handles graphics, you can just combine it with OpenGL. It's completely smooth and works as expected, without any additional dependencies.
Pro Active community and wiki
You can ask questions on their own personal forum which is full of users, and their wiki is constantly being maintained. They even have an IRC.
Pro Works on every platform
SFML 2.2 brought forth Android & iOS functionality, and SFML games work on Linux, Mac and Windows out of the box, since SFML is written with OpenGL.

Pro Great documentation
SFML is very well documented, even with short examples of use for many functions and modules. Furthermore, there are books like 'SFML essentials' and 'SFML for game development' which teach you how to use this library to its fullest.
Pro Good for OpenGL
If you are thinking about using OpenGL, look no further, you can open a window, and handle events in less than 15 lines, and it provides input, time, and even networking, plus alot more. It has become my favorite c++ library :D
Pro Great library
SFML is a collection of modular, well designed libraries you can implement an engine or game on top of. The API provides tons of good documentation and is very straightforward to use. You can get a game up and running with SFML quite quickly and with minimal effort.
Pro Clean code
An SFML project's code-base is usually clean and easy to read. All public SFML classes are under the namespace "sf" so it is easy to tell which code is yours and which belongs to SFML (of course you can stop this by typing using namespace sf;
).
Pro Available in many languages
There's support for many languages besides C++, current supported languages are: C, .NET, Crystal, D, Euphoria, Go, Java, Julia, Nim, OCaml, Pascal, Python, Ruby and Rust, and this list is constantly growing.
Pro Beginner-friendly
SFML is extremely beginner friendly and even provides pre-built libraries for your IDE of choice on Windows. Besides the fact that it's extremely well documented, they also have a set of tutorials that walk you through every module.
Pro Modern C++11 implementation
SFML is one of the few good C++ frameworks out there to actually make full use of the language. It's extremely well optimized and it plays well with anything you throw at it.
Cons
Con Lacks documentation
The API documentation is minimal, there's not many tutorials and the ones that are there are very small and only cover the basics. If you want to learn how to properly use it, you have to ask the community or read the source code and figure it out.
Con Not too many games to showcase it
Con Slow development rate
Con Relatively slow
Compared to SDL2, GLFW, it is slow.
Con No GUI editor or IDE
Does not include any IDE or media editor. It's purely source code.
Con May take longer to learn and understand
Con Messy sprite management
Sprites retain all of the operations applied to them, whether that be a new position or a rotation. This makes sprite management somewhat annoying.
Con Not specifically a 2D game engine
It isn't really an engine, more of a collection of modular, well designed libraries you can implement an engine or game on top of.
