the first one. a simple mushroom cloud, but very well defined. the lines on the bottom of it remind me of something stamper would draw :P
the second one is pretty awesome. frankensteins cold dead eyes peering at me, with his well set shadows on that solid face. nice :3
as for your latest, i'm sorry that i don't get exactly what it is you're refrencing. i understand that it is a bomb made out of a mans face (perhaps even, this is the prequal to the mushroom cloud ;)) i like his facial hair, mainly the beard that makes it look like wind rushing up the side of the bomb as it's falling.
some neat stuff ^_^