The lights are on
Limbo's greatest strengths are its haunting atmosphere and clever physics based puzzles. The game really does a good job of pulling you into its bleak world, but it is a fairly short journey with no real climax. My first playthrough took me a little less than three hours and I felt a little cheated out of my money as a result. The hidden achievements extend the replay value and difficulty but there isn't a compelling reason to return. Thus at $15 it may be a little hard to justify, but you won't forget your first experience.