New this release: a new Pathfinding behavior! Here's a quick demo of pathfinding, showing how it can help objects navigate around obstacles.
The Pathfinding behavior divides the whole layout in to a grid, and marks cells as obstacles if they are touching any solids. Then it uses A* to find paths through the grid. You can access the sequence of nodes through the behavior's expressions, or alternatively tell the behavior to move the object along the path for you automatically.
One of the coolest things about this new behavior is it uses Web Workers to run the CPU intensive pathfinding calculations on a separate thread. Pathfinding a lot of objects can take a second or more to calculate, especially on mobile devices, and normally this would make the game hang while the paths are worked out. However with Web Workers the game keeps running smoothly while paths are calculated in the background. On dual-core systems (including phones!) this means a separate CPU core can be used for pathfinding, preventing the intensive calculations having any effect on the game framerate! Web Workers are also supported almost everywhere, except IE9 (IE10 has support) and the Android stock browser (but Chrome and Firefox for Android both have support).
Anyway, it should be a very handy behavior for certain games like turret defences or making smarter enemies which can find you more intelligently. Check out the new Pathfinding example in the Start dialog for a visual demo of how it works, including mapping out the nodes.