The "Alpha" ost is definitely my favorite. It's a long masterpiece made by c418. The song was supposed to be played when defeating the enderdragon and going through the portal. I believe there was a glitch and thus the song could never be heard in the game. With the new advancements, I think it should be awesome to play the song once the player completed all the available advancements, and why not get a special disc (since new advancements allow rewards) with it.