I'd love to have played the early versions of the game, to be there to see the early tests, even just to look over Notch's or Jeb's shoulder while I hand them their coffee or something. I bet it's a fascinating experience to be part of an indie dev team.
There's an application out there that can roll back the version of Minecraft you have, Link
. It goes back to the 1.0.x Alphas and a couple of InfDev releases. I've used it a few time to go back to 1.7.3 so I could played with some mods that were slow to be updated.
It's kinda fun looking back, makes me really miss the old world generation, it was so much more "Minecrafty" than what we have now.