The pure black and bright yellow reminded me of comics, and i wanted to do a bb tpixel tribute for a while now so i smashed those two together.
of course refs! almost forgot. I drew walter out of head mostly and then used the ref to correct the mistakes and adding details like the forehead. It was to make it more stylized and not too correct, but didn't work too well. I should've just sticked to the ref completely now that i look at it.