I love snake, cant ever go wrong with snake but there are some tips I have for you, 1 this game isnt ideal for a browser due to the nature of the arrow keys, my page went all over the place when the snake had to go up or down.
2. Even though i love snake this sadly was a far fetched idea for the other planets theme.
I respect that this is made with HTML5 so keep at it and keep improving ! :D