The Citrus Engine is a GPU accelerated game engine. It uses Stage3D technology and supports 2D or 3D graphics using either Starling or Away3D, with Box2D, NAPE and AwayPhysics physics available out of the box.

Some features:

• Blazing 50 FPS in the browser on current machines, and 250+ FPS on the desktop (or Adobe AIR).
• Physics which allow for tumbling crates, pulleys, vehicles, and just about anything else you can imagine, without the limitations of a grid.
• Supports multiple rendering methods with very little code. Like blitting and sprite sheets? Citrus Engine’s got it. Prefer animating using the timeline? No problem.
• Hijack the Flash IDE and use it as a level editor, for easily laying out and iterating on level designs.
• Robust documentation includes and ASDoc API, tutorial videos, and a forum.
• Standards-based code API means developers and designers spend more time tweaking the fun stuff, and less time debugging.
• Level-based progressive downloading allows gamers to start playing the game quicker by only downloading what the next level needs.
• Pre-made commonly used objects, like a hero, coins, enemy, platforms, clouds, and more!
• Easily use embedded or dynamic graphics.
• Decoupled architecture allows for custom rendering methods, like blitting or 3D.
• Sound management
• Keyboard and input management
• Built-in particle system
• Intuitive Signals event framework

Sample

package blitting {

	import com.citrusengine.core.State;
	import com.citrusengine.math.MathVector;
	import com.citrusengine.objects.CitrusSprite;
	import com.citrusengine.objects.platformer.box2d.Hero;
	import com.citrusengine.objects.platformer.box2d.Platform;
	import com.citrusengine.physics.box2d.Box2D;
	import com.citrusengine.view.CitrusView;
	import com.citrusengine.view.blittingview.AnimationSequence;
	import com.citrusengine.view.blittingview.BlittingArt;
	import com.citrusengine.view.blittingview.BlittingView;

	import flash.geom.Rectangle;

	/**
	 * @author Aymeric
	 */
	public class BlittingGameState extends State {
		// embed your graphics
		[Embed(source = '/../embed/hero_idle.png')] private var _heroIdleClass:Class;
		[Embed(source = '/../embed/hero_walk.png')] private var _heroWalkClass:Class;
		[Embed(source = '/../embed/hero_jump.png')] private var _heroJumpClass:Class;
		[Embed(source = '/../embed/bg_hills.png')] private var _hillsClass:Class;

		public function BlittingGameState() {
			super();
		}

		override public function initialize():void {

			super.initialize();

			var box2D:Box2D = new Box2D("box2D");
			//box2D.visible = true;
			add(box2D);

			add(new Platform("P1", {x:320, y:400, width:2000, height:20}));

			// You can quickly create a graphic by passing the embedded class into a new blitting art object.
			add(new CitrusSprite("Hills", {parallax:0.5, view:new BlittingArt(_hillsClass)}));

			// Set up your game object's animations like this;
			var heroArt:BlittingArt = new BlittingArt();
			heroArt.addAnimation(new AnimationSequence(_heroIdleClass, "idle", 40, 40, true, true));
			heroArt.addAnimation(new AnimationSequence(_heroWalkClass, "walk", 40, 40, true, true));
			heroArt.addAnimation(new AnimationSequence(_heroJumpClass, "jump", 40, 40, false, true));

			// pass the blitting art object into the view.
			var hero:Hero = new Hero("Hero", {x:320, y:150, view:heroArt});
			add(hero);

			view.setupCamera(hero, new MathVector(320, 240), new Rectangle(0, 0, 1200, 400));

			// If you update any properties on the state's view, call updateCanvas() afterwards.
			view.cameraLensWidth = 800;
			view.cameraLensHeight = 400;
			BlittingView(view).backgroundColor = 0xffffcc88;
			BlittingView(view).updateCanvas(); // Don't forget to call this
		}

		// Make sure and call this override to specify Blitting mode.
		override protected function createView():CitrusView {

			return new BlittingView(this);
		}
	}
}