3. Heart Attack
"Heart Attack" served as a sort of comeback from the comeback. Unbroken was her necessary declaration, but now, it's time for her to just show off. Continuing the trend of perfect pop singles, "Heart Attack" is Lovato's best uptempo track in every possible way. It's catchier than "Give Your Heart a Break," as if that were possible, and features Demi at an impossibly high degree of vocal difficulty. The lyrics in the verses zing, and the chorus is utterly bombastic. And that bridge. Anyone who doubts Lovato's chops can listen to that and kindly proceed to eat crow. Ultimately, "Heart Attack" is what uptempo pop music should strive to be: catchy, complicated, and a damn good time.