Wow. I did not expect such a vivid discussion of my humble artwork! I'm touched, guys, thank you very much!
I knew, I knew it from the very beginning, dammit! Crayons *suck*! Why, oh why did I pick up that idea?! My next coloured artwork (don't expect it to be coming soon) will be digitally coloured. That will be my only salvation.
Blood. It's damn difficult to draw realistic-looking blood. Especially on bulging metal surfaces. But it's even harder when you can't find proper colours.
But I've got one good explanation. As the metal back-plate is concave and lies on the ground, the blood accumulated there and didn't leak out.