Though a superb game, it isn't worth the $10 price tag. Buy it if it's on sale or if you have extra money to spend.
The setting is unlike any side-scroller I've ever played - indeed, unlike any game I've ever played. Everything about the game is gloomy - from the creatures you encounter to the monochromatic lack of color throughout your short playthrough. It is also a very violent one - rather than pulling a Mario and falling off the screen, you may find yourself torn to shreds by a wheel, or stabbed by a spike as black particles of your blood fly off the screen. You might be smashed by a crusher, only to see your insides pull apart like gum when the smashing plates open again. You may simply be fried by electricity. It's something you don't often see in platformers - it brings the kind of brutality you would expect from Dead Space or Gears of War and applies it to a gloomy, two-dimensional setting.
The puzzles are perfectly balanced and entertaining. They tend to require more thought than skill, unlike the precise jumps that you may find in a game like Super Meat Boy, but you still get the same satisfaction when you pass a particular part of the map. Puzzles range from simple spike traps, to gears, to gravity manipulation, and more. You'll face challenges unlike anything you have seen in the genre, and likely will never see again (unless they make a sequel).
I would rate this game much higher if it went for 3-5 bucks. But ten dollars simply isn't worth it. I managed to complete it within 3 hours. If I went back for all the achievements, it may take another 4 - assuming I didn't skip through parts. At most, you'll get 7 hours out of this game, and that's only if you're a fan of achievements. In the end, the lack of a level editor or at least more content make a superb game kind of a rip off. If you find it on sale for less than 5 dollars, definitely purchase it. Otherwise, unless your wallet is heavy, I'd pass.