When comparing Duality vs HaxeFlixel, the Slant community recommends HaxeFlixel for most people. In the question“What are the best 2D game engines?” HaxeFlixel is ranked 16th while Duality is ranked 27th. The most important reason people chose HaxeFlixel is:
[Haxe](http://www.haxe.org) is a powerful, cross-platform and open source language.
Ranked in these QuestionsQuestion Ranking
Pro Open source
The full source code is available on GitHub, where the framework is actively developed. All of the editor, core and plugin code is written in C#.
Pro Great editor
Duality includes a powerful visual editing system that can be used for previewing, integrating, editing and testing game content.
Pro Live reload of code and assets
Pro Very extensible
Because both Core and Editor are completely plugin-based, Duality not only incorporates a clean and modular design, but is also very extensible - even if it wasn't Open Source. In fact, most of the standard editing capabilities comes in form of Editor plugins.
Pro Built-in physics and lighting
Pro Friendly to version control systems
It can be configured to serialize all data in a text-based format, which has been structurally optimized for version control systems.
Pro Used in commercial projects
It has been used in a production environment without burning the place to the ground. Supposedly artist-proof editor workflow with an API for tailoring the system to fit your team.
Pro Powerful language
Haxe is a powerful, cross-platform and open source language.
Pro 75+ demos
All demos have included GitHub link, so you can learn from the examples
Pro Uses Haxe
(excerpt from source): To help you do this, the (Haxe) toolkit contains three main components:
the Haxe Language - a modern high-level, strictly typed programming language
the Haxe Standard Library - a complete cross-platform standard library
the Haxe Compiler - an incredibly fast cross-compiler
Pro Fully free
HaxeFlixel is fully free and open source.
Pro Getting started guide
Has a starting guide for people who are completely new to HaxeFlixel; from installing Haxe to a beginner-friendly HaxeFlixel tutorial.
Pro Active development community
(excerpt from source):
There is a multitude of channels to interact with the community:
Our google groups forums
#haxeflixel on IRC (freenode.net)
@HaxeFlixel on Twitter
The HaxeFlixel organization on GitHub
The HaxeFlixel page on IndieDB
Join our development chat on Slack
HaxeFlixel group on Steam
Pro Hardware accelerated rendering on native platforms
Pro Modelled after Flixel
But with considerable improvements -- the HaxeFlixel team are constantly working improving and fixing the HaxeFlixel API, as compared to the original Flixel which is no longer updated.
Pro Outstanding community
The HaxeFlixel team and contributors are very active on Github and other community places (like Slack), and are usually able to respond to your questions within a day or two.
Pro Similar syntax to Actionscript 3
Haxe's syntax is similar to AS3, so Flash developers can transition to HaxeFlixel if they are familiar with AS3/Flixel.
Pro Powerful debugger overlay
You can watch variables, log (trace) messages, and check for memory/frame rate performance.
Pro Easy 2D game development
(Haxe)Flixel does a lot of things for you like tilemaps and collision detection, which makes it super easy to create 2D games.
Pro Cross Platform
The open source Flash API is powered by OpenFL, which allows you to compile to Windows, Mac, Linux, iOS, Android, and even major consoles (coming soon).
Pro Cross-platform IDE environment
On Windows, the IDE of choice is FlashDevelop, but if you're looking for cross-platform IDE (Windows/Mac/Linux), there's Sublime Text which includes a package for Haxe syntax highlighting, as well as auto-completion.
Pro Excellent, robust API
The API has all of the features that you'd expect from a powerful engine without sacrificing organization and flexibility
Con Visual Studio required
To have possibility for scripting you have to download entire Visual Studio and spend 10 GB of free space
Con Requires windows for development
Con Small community
HaxeFlixel devs are not as large as (example) Unity devs, so the amount of support and exposure is limited.