Not bad, but not very addictive
Nice game. Simple and dynamic.
I see a problem: you can fool the game by moving the mouse out of the game screen and placing it in a different point. The hungry square will be teleported to that new point and by this you can easily, if you are fast enough, escape an imminent cornering.
Also, this is just an improved version of Hungry Hungry Square, isn't it? With better graphics, music, game over screen and stuff like that.
It's nice but I would not spend so many hours playing this one. Maybe adding levels with walls on them or something like that would make it more addictive. Penalizing moving the square to the limit of the screen would be fine too.
Keep it up!