Skillet specializes in hard-hitting CCM buttressed by alt-rock guitars and John Cooper's gritty howl. After a clutch of albums firmly rooted in the Christian rock scene, the ambitious crew pierced the mainstream with 2001's Alien Youth; the crushing title cut sports burly grooves and riffs plunged in grainy fuzz. They later ratcheted up both the tempo and volume on the 2009 crossover smash “Monster,” a relentlessly driving examination of personal demons and weakness. Showing off their versatility, “Sick of It” retains their trademark heaviness while adding cold, jarring synth work.