When comparing HaxeFlixel vs GDevelop, the Slant community recommends GDevelop for most people. In the question“What are the best 2D game engines?” GDevelop is ranked 2nd while HaxeFlixel is ranked 24th. The most important reason people chose GDevelop is:
The whole interface is intuitive and easy to learn: each part of the game can be designed using visual editors. The objects editor is used to create the objects of the game, the scene editor help you to build the levels of your game and the events editor allows to give life to the whole game without programming.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
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 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 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 Hardware accelerated rendering on native platforms
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[1]
HaxeFlixel group on Steam
Pro Powerful debugger overlay
You can watch variables, log (trace) messages, and check for memory/frame rate performance.
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team are constantly working improving and fixing the HaxeFlixel API, as compared to the original Flixel which is no longer updated.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 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 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 Excellent, robust API
The API has all of the features that you'd expect from a powerful engine without sacrificing organization and flexibility
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 Easy to use
The whole interface is intuitive and easy to learn: each part of the game can be designed using visual editors. The objects editor is used to create the objects of the game, the scene editor help you to build the levels of your game and the events editor allows to give life to the whole game without programming.

Pro Free and open-source
GDevelop's runtime libraries are MIT licensed. It can be used freely for projects of any type and there are no royalties associated with publishing games developed with GDevelop.
Pro Powerful events system to create games without programming
No need for coding using this system which is clear and powerful: events are composed of conditions and actions. Actions are launched when conditions are fulfilled.
This is a very friendly way of making games and is still efficient for advanced usage, contrary to most other "block"/"drag'n'drop" systems.
Pro Open source plugin SDK
The plugin SDK is open source, so if you want to extend it, you can.
Pro Lots of features to build games
The engine includes pathfinding, physics engine, multitouch support, custom hitboxes, platformer engine, tiled maps, multiple layers and cameras out of the box.
All of these features can be used without programming knowledge, using the visual editors.
Pro Quickly add behaviors to objects
Prebuilt behaviors can be added to objects. This is a very efficient way to add a physics engine or make a platformer game. Lots of behaviors are included, from the most advanced (Physics, platformer, top-down movement) to really simple one (like the behavior to destroy objects when outside the screen or the one to drag objects with mouse or touch).
And you still have full controls over your game as behaviors can be modified using the events!
Pro New documentation for gd5 is good for starting
A new doc is improving for gd5 that is nice for beginners and after that you can learn more from examples. Also, gd4 wiki is still there.
Pro Constant updates
New releases and bug fixes are consistent. New updates are released anywhere within 2 weeks or 1 month from the last one. Its auto-updater also does it job very well making life a lot easier.
Pro Online version available, compatible with iOS and Android
Thanks to its open source nature, GDevelop-App.com was built over the GDevelop engine.
GDevelop-App.com is a complete game creator similar to GDevelop, available directly in your browser and compatible with iPad and most Android tablets and phone! The app is perfect for making games directly from your sofa and you can even start a game on GDevelop-App and export it to open it inside GDevelop.
Pro Multilanguage support
GDevelop is available in many languages and even community can help in translations.
Cons
Con Small community
HaxeFlixel devs are not as large as (example) Unity devs, so the amount of support and exposure is limited.
Con No support for atlas/tilemap and sprite sheet
At this point, you need to separate the tileset maps or character animation sprite sheet before importing it to the engine, but the developers are working on this feature.
Con GUI is slow to load
This makes doing the simplest things, like looking at one of your maps, hard to do. In looking into this program, it can stall a PC while trying to load a sample map.
Con No 3d, not even fake 3d
This is a 100$ 2d-only game engine. You could of course use pre-rendered 3d graphics, but your games themselves will exist only in the x and y axes.
Con It's very slow
Although suggested otherwise, GDevelop doesn't compile the games - it just adds wrappers so each OS can run the HTML5 game it creates. That means it runs much, much slower than other engines that do compile games.
Con No cross-compiler
The Windows and Linux versions of GDevelop can each compile a native application; but the Windows version cannot compile for Linux, nor vice versa.
Con Optional subscription not mentioned on main site
While the engine is free and open source as stated on the main website, it does not mention that some optional features and services are actually activated through a paid subscription (two tiers: 2€ and 7€). Those features are: no nag screen shown when debugging, additional metrics available on games dashboard, access to more than 2 cloud exports per day (unlimited local export can be done without subscription, provided the right packaging tools are installed and configured), easy removal of GDevelop splash screen (can be done manually without subscription).
Con Behaviors of Objects are rather generalized
Since it has a fully GUI editor, the objects you are allowed to add in your game are pretty generalized (PhysicsObject, TiledSprite, PlatformerObject, etc). This limits the freedom of a game developer while making a game, as the object msut follow the preset behaviours imposed on it.
