Download the base template or fork the project on github
No sprites (but feel free to use some! )
Use a simple component for the snake, just 2D, no display, and make it have an array of entities, all being one square of the snake.
Sprites, background (source, source)
I think you can do that one without help. :)
Sprites (source, source, source)
Get the source code of Crafty and hack the Twoway component to make the character go faster to the left than to the right.