There are some artists who love to be chameleonic and yank the rug out from under their fans; Prince, David Bowie, and the late Miles Davis are three of examples of risk-takers who had no problem coming out with albums that jolted fans right out of their comfort zones.

But others make a career out of finding a comfortable groove and pretty much sticking with it -- AC/DC, for example -- and Unleashed are clearly of that mindset.

The Swedish death metal veterans have maintained an "if it isn't broke, don't fix it" outlook, which is why 2008's Hammer Battalion doesn't sound radically different from their early-'90s recordings.

Unleashed's basic recipe -- thrashy death metal with Viking themes and a lot of ultra-fast, mosh pit-friendly tempos -- hasn't changed radically over the years.

They have picked up more of a black metal influence along the way; black metal's onslaught-of-doom harmonies sometimes find their way to Hammer Battalion.

But all things considered, this 44-minute CD is quite faithful to the band's history and does nothing to alienate or frighten away longtime fans -- and if Hammer Battalion is somewhat predictable, it is predictable in a good way.

One expects Unleashed's albums to be brutally heavy but not devoid of musicality; Hammer Battalion fits that description.

Johnny Hedlund's lead vocals are intelligible -- unlike a lot of death metal vocalists, he doesn't render the lyrics impossible or difficult to understand -- and the Swedes are relatively melodic on Viking-themed tracks such as "Black Horizon," "Your Children Will Burn," "Entering the Hall of the Slain" and "Long Before Winter's Call." Hammer Battalion doesn't pretend to reinvent the wheel, but it's a solid, reliable effort from a band that has spent many years in the death metal trenches.