For the WebGL build it may be an issue with the compression format. A fix that works for me is going to:
Build Settings -> (switch platform to WebGL) -> Player Settings... -> Publishing Settings -> Compression Format -> Disabled.
Hopefully that works for you!
The Windows build does work though, so I played it there. The movement was tricky to get down, but very satisfying whenever I got the dice to launch by flicking the platforms up. Overall, a cool take on platforming with a rolling dice, moving the platforms instead of the player.