I really love this. I was working on a wolf with arrows in it for an upcoming poster when I saw this go up. My friend was over and I was like 'holy shit! look at this' and she was all 'that's much better than the one you're doing. you have to start over.' And I was all 'duh.'
Out of curiosity, did you find that using the paint pen was faster/easier than actually just screening it?