Welcome to Limbo, a monochrome place where Spiders are over ten feet tall and love to impale small children with their legs. According to Catholic theology, Limbo is the edge of hell. From what we can tell based on early reports and developer interviews, the story revolves around the main protagonist rescuing his sister from Limbo.
Unfortunately the story isn't explained in-game; the closest it comes is when the boy comes across a little girl. That's where the game ends. Playdead has left whatever happens next to our imaginations - a little dialog at the start or end would have worked to explain who the unnamed protagonist/this girl are, and why they are in Limbo if they got out at the end.
Untold story aside, Limbo has a unique monochrome visual style - making it the first Xbox 360 game you can appreciate on a black and white TV. Said style has its advantages and disadvantages. On the upside, buttons are clearly marked by being white against the black background. On the downside, it makes telling things apart difficult the first time through - one thing that looks like skin piercing spikes may just be a lock of grass, and vice versa.
Over your journey through Limbo you will encounter giant spiders, hostile natives, and mind controlling worms, along with a variety of traps to fall victim to including buzz saws and electrified surfaces. Overcoming these obstacles requires a mix of quick thinking and timing. Mind controlling worms won't kill you, but they will take control of your movement and move you in a direction (typically toward a pit) that may lead to your demise if you aren't quick on your feet. Spiders have to be taken out with a bear trap; these play out like boss battles but you'll only have a few Spider encounters. One of these will see you tied up.
Due to the Limbo's puzzles requiring a combination of precise timing, flicking switches, and luck, you will die. A lot. That said, it's very entertaining to see your little boy get ripped to shreds by a saw blade, electrocuted - or worse. These gruesome deaths are inherently censored by the visual style but the sight of a black figure being chopped into little pieces is satisfying.
Despite the difficulty, the unique puzzles will keep you playing - if only to see what the game will throw at you next. As you progress, the puzzles go from simple pushing blocks, to physics puzzles which incorporate gravity manipulation. Ultimately a lot of the puzzles are trial and error affairs, trying one thing after another until you find the blindingly obvious solution is just part of the fun.
Overall, while Limbo's back-story is strangely absent, it can stand on the unique visual style and deceptively difficult platforming/puzzle gameplay alone. Should you take that walk through Limbo, be prepared to be tested on your platforming skills because timing is everything and some imaginative puzzle design that will have you hooked until the end.