Today I noticed that quite a few of the http://www.babylonjs-playground.com/ examples are crashing with "XXXX is not a Constructor" errors (replace XXXX with the name of something from the babylon api). I noticed this while searching for examples of the VR free camera, but is seems like there are many other broken examples. Looads of older custom playgrounds I found around the forums are crashing now as well.
e.g.
Compilation error
Line 9:17756 - e.Gamepads is not a constructor
I noticed that the playground is running 2.5-alpha rather than 2.4, maybe there should be a version selector on the playground site?