I think the riff is adequate, but nothing amazing. It's nothing compared to I Will Follow, which is as simple a riff as they come. Vertigo's riff sounds like its "supposed to be" hard rock, "supposed to be" punk, "supposed to be" garage, "supposed to be" young, "supposed to be" rocking, "supposed to be" fun, "supposed to be" U2 letting their hair down, "supposed to be" a retro throwback anthem, "supposed to be" proof that U2 still rock. Yes, it sounds like all those things, and that's why i don't like it. It sounds studied. It sounds formulaic. It is bled dry of anything rock and roll. It will never be I Will Follow. There's no urgency. There's not even a pop song. It's a front.