If you're not afraid of the dark, "Limbo" could change that.

Because darkness is the single resonating detail of the two-dimensional, side-scrolling adventure by PlayDead Studios and distributed online by Microsoft Game Studios via Xbox Live Arcade for the Xbox 360. It pours over the landscape and plot of "Limbo" like a sticky venom, trapping gamers in its minimalist but mesmerizing black-and-white expanse. Shadows are not what they seem, and in a game of nothing but shadows, that produces a sense of dread that's palpable and lurid.

"Limbo" puts players in the shoes of a nameless boy depicted as a black splotch with white eyes. His origins are a mystery, but his goal is clear: He must rescue his sister from a doom undefined but implied by the environment. So he embarks on a sideways journey without soundtrack or dialog, just the eerie sounds of death and potential destruction.

But this adventure is not a stroll through spooky; the boy confronts assorted obstacles and puzzles he must surmount or solve to acquire knowledge necessary for later horrors.

These are not conventional challenges, either. Many clues are not apparent, so the boy will die often as players develop a feel for what to expect as the leftward-moving story unfurls.

The two-tone imagery is enthralling, the better to distract players from the tasks at hand.

"Limbo" is film noir at its finest in this application, without preconceptions or uniformity. Lilting tendrils of dread dangle over every inch of the boy's path; fear is a precondition of his every move.

That said, "Limbo" is not a child's game. It's sure to be a nightmare-maker for young minds and maybe a few adults. You could play "Limbo" alone in a dark room if you want, but that fairly begs psychological torture.