Originally four cellists, now three cellists and a drummer, Finnish quartet Apocalyptica have worked hard to become more than a mere covers band since their 1996 debut, Apocalyptica Plays Metallica by Four Cellos.

Their early material established them as astute interpreters of the thrash metal genre, finding a gold mine in the tension between their subject metal and their instruments of choice, but as their reputation grew they sought to become full-fledged members of the heavy metal community.

By the time of 2007's Worlds Collide, Apocalyptica had completed the transition from chamber room instrumentals to pulsating neoclassical metal, a feat amazingly achieved without the use of conventional guitars.

With drummer Mikko Sirén in tow, the three founding members play distorted cello in the style of Slayer and Metallica, alternating bass picking, distorted riffing, and clean melodic lines with or without a collaborating vocalist.

The one spot on Apocalyptica's record to date has been the distinct lack of a great album to complement a catalog of musical accomplishments, but Worlds Collide is very much the antidote to that problem.

Driven by the slick modern rock single "I'm Not Jesus," sung by Slipknot's Corey Taylor, the album expertly bridges the gap between accessibility and the group's more progressive instincts.

Atmospheric opener "Worlds Collide" is as succinct a summary of Apocalyptica's musical style as can be, literally and sonically, contrasting sections of polite melodicism and bone-shaking thrash.

The album's coup de grâce is its one piece of non-original material: "Helden" is a cover of David Bowie's "Heroes" auf Deutsch, with Rammstein's Till Lindemann handling lead vocals, and the cellists' rendering of the main theme is so seamless, so perfect, that it's hard to remember just how much differently the original was handled.