I've yet to see Starseed Pilgrim have it's own post, other than mentions in the Indie Thread. I started playing Starseed Pilgrim almost two weeks ago, and it's consumed me since and I've championed the game myself. I learned about it from Jonathan Blow's Twitter where he was raving about it and called it one of his favorite games of all time. I then saw this writeup on Rock Paper Shotgun (http://www.rockpapershotgun.com/tag/starseed-pilgrim/) and became intrigued.
I make the analogy to the movie "Searching for Sugar Man" which is a great documentary about a 70s rockstar who became "as big as Elvis" with South Africans but was unknown in his home country USA. Search Twitter and you'll see many people calling Starseed Pilgrim there GOTY 2012/2013 (I think it originally came out in 2012).
So what is Starseed Pilgrim? Starseed Pilgrim is a game with no handholding. The genre isn't specified. You start as a pilgrim who can plant different colored seeds that grow into the blocks shown in the above image. As you plant seeds, the darkness seen in the image spreads through your blocks, and when it touches your character you enter a "flipped world" shown below:
That's all you're pretty much told when starting Starseed Pilgrim - the rest of the game's objectives have to be discovered by the player. There has been comparison to Fez's "second game", but with Starseed Pilgrim there is no obvious first game like Fez's platforming. Starseed is very much a game though that is highly mechanics based, not just abstract puzzle solving. You could also compare the no handholding to Demon's Souls, but the game is not mechanically difficult. A good comparison would be if the original Metroid was released with no manual or player guidance.
Figuring out this game has been one of the most rewarding game experiences I can ever remember. I still am playing the game with more to do after 10 hours.
I can't recommend this game enough. It's $6 on http://www.starseedpilgrim.com/. This post sure sounds like an ad but I just really love this game and hope others try it out.
Edit: Out now on Steam! http://store.steampowered.com/app/230980/
Added by popular demand! (4/16/13): Starseed Pilgrim guide
Tip: Gain from loss one does not measure but broken hearts yield Starseed treasure.
RPS Wot I Think: http://www.rockpapershotgun.com/2013/04/19/wot-i-think-starseed-pilgrim/