As far as I can remember, there has only been one other forum who's done this. It's simple: just post a picture that will defeat the one before it. If its obscure or very strange, simply type down how it wins over the previous one.
It's easy to get into a near impossible-pic to beat. For instance, Chuck Norris. Nothing beats Chuck. So no pictures of Chuck. But try to be creative; the devil 'pwns' God in the sense that if the devil didn't exist then God's way'd be the only accepted one.
Anyways, don't post a repeat either. So no
Devil
God
Devil
God
Kinda thing. Again, try to be creative.
Anyways, I'll begin.
http://simonz.web.elte.hu/wallp/promo-vader.jpg(A good idea would be Luke Skywalker. Or a missile. Either will do.)