So what, exactly, do you do in terms of platforming? Well, the controls are simply the 360 analogue stick and a grab/do button; the game's keymap option screen is a minimalist joke in itself.
An early, simple puzzle has you come across a corpse that's buzzing with flies hanging from a rope attached to tree branch, and unreachable platform above it. Your task is to manoeuvre a nearby mantrap beneath the mouldering body and leap onto the rope - dragging down the tree bough, dipping the maggot-filled legs into the waiting teeth of the trap, and once the body is detached swinging on the rope to freedom (of a sort) on the ledge above.
Rotten trees can be pushed over, and rolling boulders that thunder towards you must be dodged, but repetition never becomes an issue. As each new puzzle emerges from the gloom neat twists on existing gameplay veer your problem-solving in different directions - one minute you'll be snapping off arachnid legs with your mantraps, the next it will have cocooned you Frodo-style with its web and all you can do is hop over the landscape as if trapped in a zipped up sleeping bag while desperately trying to avoid the rolling architecture.
Later on, as scenes become more urban and industrial, vast moving cogs and magnets come out to play, the screen starts to revolve around you and… spoilers, spoilers, spoilers. Needless to say, Limbo isn't quite as trapping and motionless in its approach as its name might suggest.
If there is a worry about Limbo it's that its puzzles might become too complex in the closing stretch of its four-hour runtime, yet the first 40 minutes I've played this year at GDC are user-friendly in a way that only the most incessantly playtested games could ever be.
The way the game nudges your attention to relevant puzzle items through the usage of butterflies, rumbles, falling leaves, subtle camera-points and the movement of the boy's beautiful glowing eyes is fiendishly clever, and the deaths associated with them rarely anything but stabby/shreddy perfection.
Above all, Limbo is mysterious - and developer PlayDead wallows in the mystery. Is the boy dead? "Maybe." Was that his sister on-screen? "Who knows?" What more can you tell me about the story? "Uncertain of his sister's fate, a boy enters Limbo." Do I need to get something to float on this water so I can stop drowning in horrible ways? "Who can say?"
The only thing I can nail down here and now is that Limbo already feels like it will be up there with the most interesting games of 2010.
Limbo is due out exclusively for Xbox Live Arcade this summer.