watch the HQ version
first I watched the version here on ng, and my first thought was crap, then I read your comment and downloaded the HQ version which is really a lot better quality wise. Anyway I really liked the idea of an all square world, but I did find some round things, the pupils (in the eye), the hookers legs looked rather round with the stockings on, the trees, maybe you could have emphasized the "i'm square"-scheme a little more on those.
I like how the lightbulb was circular and then he invents the wheel, very nice. I hope that was on purpose.
I also liked the double meaning of "The End of The World" sign at the ending:
invents the wheel -> fuck the squares, world as they know it is over
and obviously that it's the edge of the world
but I did think it was obvious that the "globe" was going to be a big old square. Also the head of the main character should have been more box-like, e.g. when you see him from the side you see more than just a line.