There is no support for blendMode on cpp target (because I chose the drawTiles method for rendering)
Setting antialiasing property of FlxSprite will affect all FlxSprites which share the same bitmapData (see par.1)
On cpp target FlxText will be usable only for statical text fields (because it use bitmapData generation/manipulation which is slow on cpu)
For dynamic text in cpp use new FlxTextField class which extends FlxText but uses standart TextFields from flash. It is about 2x faster (if you often change the text), but it need more control. Use setVisibility() / getVisibility() and kill() / revive() methods for controlling it's visibility. FlxTextField objects are drawn above all other FlxSprites and FlxTilemaps. And I almost forgot to say that FlxTextField doesn't support rotation (that's pity).
Added "width" and "height" getters/setters on cpp target for better camera manipulation. For example, if you want to change camera's size and position (for a game with multiple cameras or in other case).
Added "fog" property to FlxCamera (in cpp). Try it for yourself. Nothing special.
There are differencies in scaled FlxCamera posiotioning between flash and cpp.
Setting FlxCamera's alpha will affect only it's backgound but not everything else that is drawn on that camera (FlxSprite, FlxText, FlxTilemap etc.). It's NME's issue.
Because I chose drawTiles() method there are several additional methods for FlxSprite (FlxText, FlxButton) and FlxTilemap for draw-order control:
TileSheetManager.swapDrawableObjects(obj1:FlxObject, obj2:FlxObject) - changes the draw order of tileSheets of these objects
TileSheetManager.swapTileSheets(id1:Int, id2:Int) - swaps the draw order of tileSheets with these ids
TileSheetManager.setTileSheetIndex(id:Int, index:Int) - changes draw order of tileSheet with id to index
TileSheetManager.getMaxIndex() - returns current maximum draw index
FlxSprites and FlxTilemaps has getTileSheetIndex() method which returns draw index of it's tileSheet
New graphical assets management system: now you can pass String or Class as a Graphic parameter to appropriate methods of FlxSprite, FlxTilemap, etc. (e.g. loadGraphic(), loadRotatedGraphic(), loadMap(), etc.). This should make easier your work with graphics. Thanks to Maggo (https://github.com/Maggo) for idea.
For FlxSprites which can rotate better use loadGraphic() method on cpp.
Not rendering system specific but numpad and functional (F1-F12) keys are broken. It is also NME's issue