Lot's of new things
1. Shooting with 'Left Mouse Button' and 'Force Full Screen' feature.
2. 2D images in editor so that developer can create a regular game UI.
3. SWF export now exports full SWF file, all game-assets are inside the SWF.
4. It's now possible to have Full Screen + Mouse Lock in projects uploaded to Newgrounds game-portal.
5. Lightmap feature is implemented in the editor so you can have all models lightened without the use of dynamic lights.
6. Shooting + Aiming Target feature is ready in the new beta editor.
...I'm sure that I forgotten something but these are all great new features and they are fully functional