There is a pure and innocent emotional core and that reflects on the kind of design developer Playdead put into it.
The only text you'll see isn't even in game. It is the matter-of-fact introduction: "Uncertain of his sister's fate, a boy enters LIMBO." And really, that's all that should be said. Limbo defies any type of logical breakdown. One moment you're running in terror from a giant spider lumbering over obstacles and straight out of a child's nightmares and in another you're chasing a delicate butterfly as it flutters away frantically.
So much like another side scrolling series that needs no mention, there is that classic "save the princess" motivation. However, there is an earnest follow through in the gameplay. True to its expressionistic visuals, the storytelling is done through moods. I would consider "lonely" to be a key descriptor. Early sections have the boy confronting terrible monsters, an even crueler middle section has him being shunned by other children, and the coldness of the third section is perhaps the cruelest.
Rather than deterrence, it creates a sense of longing as the player solves surreal gravity puzzles and even tension for the timing based platforming parts that are mixed in. The puzzles won't cause most players to have to stop very long like Braid. More like the Portal games, Limbo paradoxically is a puzzle game that discourages over-thinking.
There is beauty in the simplicity of Limbo's design. The only inputs are the left stick for movement, a jump button, and a grab button. It ties in really well with the black and white visuals, the droning sound design, and the side scrolling genre as a whole. Its all so bold and unified that there is a hypnotic quality that drives the player forward. The obstacles necessitate a thoughtless progression as experimentation in figuring out the rules of each puzzle. You'll be working on a gravity puzzle one moment and then the boy's limp body will be completely subject to gravity the next. But keeping with the steady pacing, the boy will be back to where he was at the start of the puzzle in batting of an eyelid.
For all I blabber on and on about it, Limbo demands to be played rather than described. Its incredibly polished (and I think that term gets used too exclusively for big blockbuster games) and yet also heartfelt. For anyone who isn't interested in seeing a boy get maimed for a few hours, I can't stress enough how tender of a game Limbo is. It will likely be included in any number of holiday sales and I hope you do get a chance to play it.