Remember, one ball is meant to hang lower than the other, so that when you walk they don't knock together. Ouch! o_O......I agree with what Manupix says.
There are many issues in this piece. The most serious is perspective. You need to draw a precise sketch to use as a guide for the pixelling. One-point persp is what you need (not the best of links, look around for more!). For instance, if you drew the vanishing point from the triangle as it is, it would fall near the top of the blue ball, and that's where the horizon line should be (and the table edge below that). The black ball should be much larger too.
The circles look jaggy. Since this piece is all about circles, they should be perfect ;)
The light sources are somewhat inconsistent: where does the reflected light on the lower half of the balls come from? Only the green carpet can reflect there, and it doesn't produce speculars. The red balls can't be that similar, as they would reflect each other. The shadows can't be top-down if the reflections are sideways. In fact, you can't do this without a ref image (or from life!). Here's one, find one that suits you and try to understand the light.
Colors: it's possible that you need that many for all the balls, but the carpet greens are too many, and not true to life. They should have less saturation than the balls (both for realism, and good color composition). The tone below the blue ball is probably the best. Again, refs!
Also forget dithering at this point, it just gets in the way.
This piece would make a good WIP forum thread - unless it already did, sorry I didn't take the time to check ;)
its meant to look like it :S only did it because i was bored?