I think alot of people are missing the point with Happy.
Electra Heart's final song was Fear and Loathing, a really depressing, morbid track. Happy is Marina coming full circle, when you compare the two there's a massive contrast. It's the album launcher because she's letting the listener know straight away she no longer feels how she used it. After that it launches into Froot, a camptastic Disco banger. I think the rest of the album will be fairly upbeat, lyrically and sonically.
The days of Dr Luke pop bops are over, I think a few people have yet to move on.