Amazing concept ! The only 2 issues I would have with it is that depending on the mouse sensitivity the handling of the mouse can be a bit unwieldy at first, and when touching a red square the snake's head is positioned just after the red cube following the current direction. In my memories that's not what happens in Snake, and if the red cube is in a corner that means game over.
And the game becomes a bit boring after a while once we figure out the whole thing. But what really matters is the initial funny concept, once again a great idea and good execution !