I'm not sure if I like this one. It's meant to illustrate "day two" in which God separates the sky "vault" or "dome" from the water. I think the joke is the view that creation can seem arbitrary: that there's no rhyme or reason for things being the way they are except that a creator decided it would be that way. Of course, when the Son of God gets too carried away with his Blow-Up style vocal delivery and silly artistic expression, God comes in to put a stop to it, suggesting that there's a "right" way to do it. I'm with God on this one. Everywhere else in the strip, creation and the "interference" of the gods is more natural and limited. They're not what I would call "all-powerful."
Of course, the Son is also making devil horns and stuff, typical childhood graffiti, so there's that silly joke to enjoy too. (The devil face brings up theological questions about this strip that I'm not equipped to answer.) And the yellow is the color of the usual smiley face.
My guess is that no one would think about the strip as much as I do/have, so everyone else probably likes it as much as any other.