Probably this could work:
FlxG.stage.opaqueBackground = 0xffff0000;
acceleration.y to gravity value. And
velocity.y to projections of velocities on axes. To calculate those projections you can use
What you want is called (de)serialization. There are some means in Haxe to simplify the process for JSON (http://api.haxe.org/haxe/Json.html) and its own format (http://api.haxe.org/haxe/Serializer.html).
There are some libs for CSV at github (https://github.com/search?utf8=✓&q=haxe+csv), don't know how automatic they are though. You can also read the FlxTilemap CSV parsing code to get the idea.
Yeah, you should declare playerBullets as FlxTypedGroup<FlxSprite> or FlxTypedGroup<Bullet> (where bullet is derived from FlxSprite) and then pass either playerBullets or the function that does recycle() on it - to the object where it will be used. So there are no casts necessary
The short version is: just forget you have FlxG.state and do the usual OOP
I'm actually using it together with FlxMouseEventManager. What is your problem?
If I understand the question correctly then you want to change
animation.frameIndex directly. For this to work there is no need to call animation.add() or animation.play() at all.