It has the best voice acting and script writing I have ever heard in any game, let alone an indie developed one. Combine this with the superb stylish visuals and engaging emotional plot this makes one amazing game and a very moving experience.
Their really is not much to say, it is not a huge diverse game. Some might call it short and simplistic, but I say it is perfect at what it tries to be.
But don't buy into my hype too much, or you will certainly be disappointed, as nothing could live up to that last paragraph.
So if you like a good emotional story, check out Eternally Us.