It sounds like a "real album" (as in cohesive, has clearly defined themes, related/repeated motifs, etc) while still being pop and accessible. I think a lot of the songs will be growers unlike Teenage Dream where the hooks hit you instantly.
Since the reviews came out I thought it would be the third single, we'll see if I'm right. But it does sound like the most instant thing apart from Roar which is the only song on the album that SCREAMS "global #1 mega smash".