Yeah, the game works perfectly fine after refreshing. The music stops after a  death/restart, but I guess that's intended. 

The crash happened to me after I ate one newly spawned donkey and then waited for a while, planning my next move. It could've happened because the game was attempting to spawn another donkey in its place after its replacement has already spawn, but I'm just throwing the blind suggestions based on what happened and the function names that caused the error.