If you're a Warhammer 40K fan, you've dreamed of taking up a chainsword and carving Orks into bloody chunks of flesh and bone. Warhammer 40,000: Space Marine plants you in the heavy boots of an Ultramarine and lets you do just that. The viscera fly in this third-person shooter/melee hybrid. They stain the ground and splash against your screen, yet the brainless hordes continue their assault, crying out their familiar "waaagh!" before presenting themselves for slaughter. Space Marine is simple fun, and a treat for fans of the franchise--and for anyone who delights in the ceaseless bloodletting of bad guys. It is, in fact, a little too simple. As entertaining as it is, the game lacks the variety, the memorable moments, and the sense of scale of the finest shooters. After you annihilate yet another great mess of greenskins, the question arises: Is this all there is to it? With some exceptions, yes, that's all there is to it, and it's hard not to wonder what might have, should have been. But the action is so satisfying, and the atmosphere so grim, that you'll want to see the adventure through. What Space Marine does best is capture the spirit of its universe. The Ultramarines' weathered armor is so heavy and hardy, they don't so much wear it as it wears them. As you push through battle-worn trenches, the Orks' makeshift machinery erupts from the ground, shaking the earth. Roaring greenskins in rocket packs rush past, providing a touch of comedy amid all the carnage. And such carnage it is. Enemies erupt in soggy displays of goo, yet the waves continue, your foes' bloodthirst overcoming their sense of self-preservation. When you carve your chainsword through these forces, the buzz is so authentic that you can almost feel the green flesh being torn away from your foes' skeletons. The visuals and sound both work hard to promote this brutal atmosphere. The story, on the other hand, is as dry as the battlefields are sodden. (To wit, the opening cutscene begins with a sequence featuring the ever-exciting storytelling device called "words displayed on a monitor.") As Captain Titus, your role is to mow down Orks and, later on, the forces of Chaos. You and your comrades speak in lofty, stentorian tones and act as mere pawns of the plot. The main players are voiced well but are as forgettable as can be, everyone filling their assigned roles but rarely giving you a reason to care about their destinies. The story is too simple for the plot "twists" to feel anything other than inevitable, and while the cliff-hanger ending sets up a sequel, you probably won't feel all that curious about what might happen next.