On his energetic second full-length, guitar-totin' Mike Serviolo splits the difference between free jazz and ballistic heavy metal, adds a pinch of prog and brings the whole shebang to an aggressive boiling point with the finesse of a saucier. Propelled by the rhythmic thrust of bassist Bob Gumbrecht and drummer Ron Smith, IZ avoids mosh-pit convention with an arty brand of instrumental riff rock that generates suspense while it confounds expectation. Dark and sinister-sounding one moment ("Engine 23," "You Will Pay"), introspective the next ("Lesson in Futility," "Weave"), these eclectic and pleasantly gritty explorations deconstruct heavy-bottomed hair metal with enough off-kilter crunch to please brows high and low. Forget shoegazing, nü-ness or pretense. Serviolo's playful sense of tempo-mongering and genre-juggling combine for musical surprises that are more fun than bullets in a bonfire.