Love the simplicity of the game, as well as the re-imagining of snake. Pixel art is highly intuitive and charming. Well done!
One possible improvement would be to store a buffer of keystrokes that the player enters, for example, [D, R, D] would make the root go down one frame, right the next frame, and finally down for the last frame. But needing to do frame-perfect inputs is part of the classic snake mechanic and players expect this, just offering an alternative perspective. :)