I found and reproduced weird bug. When I make famili consisting box objects, I can make actions related to physics behaviour, although when the same commands are used with family of sprites the game crashes.
Here is related cap.
http://jump.fm/CMAUW
It doesn't crash for me. Are you using 0.99.96?
Develop games in your browser. Powerful, performant & highly capable.
well yes, might try reinstalling though if yours work.