Very smooth and simple. It looks great and feels great. I really like how the player has to deduce the the symbol meanings. It would be nice to have some indication of how many more levels there were, maybe a set of dots on the side that get filled in after each level? I think a couple extra more difficult levels are needed, most of the levels were pretty quick to complete. I'm thinking another rule/mechanic could help too. Maybe a color shifter square (or vertex) for the snake that swaps between colors and you have to hit certain vertexes with specific colors. Just an idea, not sure how good that would actually feel to play with. Overall great job!