do you know anything about sound design? because, yes, limbo's sound design is of extraordinary quality and its execution is very unique, often subtle but extremely polished, and masterfully implemented.
the slow and brooding buildup to a dark ambiance with hints of sinister strings and distant, muffled, warm harmonies and the ever-present environmental sounds, the faint ambient noise... there's the slow and eerie passages with warm and organic sound and the cold, empty stretches of unknown, potentially dangerous terrain followed by sudden outbursts of dark and violent melodic and sometimes disharmonic flashes. then there's the excellent use of reverberation, doing a fantastic job of setting the mood in general, especially later on.
but the sound design has gameplay implications as well and is often used very cleverly and to great effect. one scene in particular comes to mind: the first encounter with the spider...
you walk across a long stretch of grass in the forest. but it's eerily quiet, so you're alert. there's hardly a sound and no obstacles or dangers in sight, so of course you notice the trap high up on a tree, but for now it seems useless, so you continue on ahead to find the big spider blocking your path. it stomps and shakes the ground with its long, dangerous looking legs. after another stomp everything turns quiet again for half a second. and then you hear it: a metallic *CLANK* from your left speaker, from somewhere off-screen. you know what happened almost immediately: the trap you just walked past must have fallen from the tree. and you realize what's next...
yes, truly masterful sound design