Do I have to learn Flixel (AS3) before HaxeFlixel?

No, you have to learn HaxeFlixel to use HaxeFlixel, although previous experience with the AS3 version will help.

Do I have to learn ActionScript before Haxe?

No, although previous experience will help.

Do I have to learn OpenFL to use HaxeFlixel?

No, HaxeFlixel abstracts it completely.

Are there any tutorials?

I found a bug, where to report?

On the official GitHub repository.

Is HTML5 supported?

Almost, it still is in development.

Will next-gen consoles be supported?

Eventually, yes! Read more about it here.

My sounds are lagging!?

On some platforms you need to manually cache sounds: FlxG.sound.cache("sound"); or FlxG.sound.cacheAll(); to do all at once.

My player falls off-screen after walking a certain distance!

Collisions are limited to the area defined by FlxG.worldBounds. For example in platformers where this area needs to be larger, you need to adjust it manually.

Can I make 3D games with HaxeFlixel?

No, the framework is limited to 2D graphics.

How do I protect my assets from being stolen?

If you add embed="true" to the <assets path="assets"> tag of the Project.xml, the asset files are embedded into the .exe.