A good start, you have most fundamental aspects of the game done. The game needs drastic improvements though. Visually its doodles, therefore lacking the pleasing affect. There are no sound effects or background music. Something you might want to consider to add. The snake moves to quickly, reduce the speed of the snake. Also introducing a score might be a good idea, as it adds replay value and can show what achievement you made in the game. The difficulty of the levels is a good idea, you could use those blocks to create for other shapes or corridors for additional levels. Good start, but more of simple things needed to get a gameplay :)