Crowning Moment of Awesome: Even if you don't want to read the rest of the series, and you might not, it's worth tracking down issue #3 of the original series to see Wormwood's guided tour of heaven and hell.
Babs flipping off Nigel the Beast with Seven Heads and telling him "fuck off"
Crosses the Line Twice: Pope Jacko and his penchant for coke-fueled orgies with scantily-clad nuns, Wormwood swapping a dude's nose with his dick, God as a constantly masturbating, levitating moron, killer eunuchs, every single TV show Wormwood's responsible for... look, it's Garth Ennis.
Fridge Logic: Wait... Wormwood can't cure Jay's perfectly mundane retardation by getting HIT ON THE HEAD!
Fridge Brilliance: In the final issue of the first series, Jay is cured by other means - and begs to be killed. In a cured state, he remembers all the things he went through, and how little it amounted to in the end. The only way he can stand to live is as a retard.
Wormwood: Jay's suffered for the human race twice now. He's done his bit. And me... Well, as I never ger tired of saying, I am the Antichrist. So it looks like you'll have to sort out your own problems, folks. Because me and my pal Jesus? We're not about to do shit.
Nightmare Fuel: The visions of Hell that are shown to Paul Carnovitz in The Last Battle #1, particularly if you're a parent of young children.