Limbo is a 2D puzzle platformer with a highly stylised art direction - everything is a mix of black, white and grey. It also has a pretty old-school play philosophy: you'll die repeatedly until you learn the way through. Everything being shown in such stark shades means that things could appear very flat, but the use of objects in the fore- and background, plus the edges of the screen appearing unfocused, give Limbo a sense of depth.
Controls are simple: A is jump, B is use. You can climb up and down at the appropriate places. However, it isn't necessarily easy - the puzzles aren't necessarily roadmapped, so trial and error is the only way forward - and it isn't for kids, given the many and varied ways your character (a boy) can die.
I'm 50% of the way through (49%, according to the display) and am enjoying the ride. The scenes with the giant spider were genuinely tension filled - impressive, since you are really only watching in silhouette - and I'm curious about where Limbo is going to end up.
The core question I've seen (and asked myself) is if Limbo is worth 1200 Xbox Live points. Right now I figure I'm going to take about 1 - 2 more hours to finish the game, for a total of 3 - 4 hours total play time. Reports are that a clean run takes about 1.5 hours (and is an Achievement if you do it with less than 5 deaths). At 1200 points, it depends on how much you like puzzle platformers - Limbo is a very solid addition to this category, executed in a distinct and creative way. Perhaps a better 'value' for Limbo is 800 points if 2D platfomers aren't necessarily your bag. I'm happy with giving 1200 points to a title that takes the 2D platformer somewhere different.
(One point: if you buy all 5 of Xbox Arcade's Winter / Summer collection - 5000 points in total afaik - you'll get 1200 points back, making it 760 points a title. If you only buy 3, you'll get 400 points back, for 1067 points a title.
These are the 5 titles in this deal.)
Rating: Buy - 1200 points if you are keen, 800 or fewer points if you're happy to wait and see