To clarify myself on the tags, would this be monochrome or polycromatic? The only real color is red . . .

At most, Monochrome. There's no color gradation with other colors outside of the primary red & black, with white contrasting for the chars. Personally though, there's too much white with the char depictions to fully warrant monochrome as a tag here. I can see why you'd want that tag here, but this is one of those borderline cases. If the white was just accents, sure, but it's a very primary color here.

I'd have to hear an opinion from another mod or two to be sure. These are monochromatic elements (BG and Chars), but the image as a whole isn't technically monochrome with the two elements together.