This is awesome and one of my favorites, but the speech bubble and its text look off to me and detract from the image as a whole.

It's good to know I've inspired :D

The greenish yellow colour is the background, but, I spent ages making sure that nostril was in restriction, god. :P

Gotta love wide pixels. Nice job!

My biggest problem is that purpe for the anti-alias in the text just doesn't work. Why not use the gray there? You've already used it in other places.

Ah, and I found a place where it'll break the restrictions. You can only have 4 colors per 8x8 block, and one of the has to be a global background color. Everywhere else in the image, this rule is being followed only if the background color is that greenish-yellow color. But right over the nostril, where you have a bit of gray, that block has 5 colors, and also none of them is the background. If you erased the red\purple dither at the top of that block, it would fix this without changing the picture too much. That's all I could find. Close enough, to me. :)

This is fantastic, I love it. I belive its within color restrictions, and has an overall nice feel to it, to be honest you've made me want to try this.