First, this is the best episode I have seen in a long time. I am physically excited. There was SO much revealed at once that it is really hard to take in, but they did a great job in pulling viewers for the next year.
Secondly, we finally found out what Jack's purpose was to return to the island: he had to encourage Richard. Richard was giving up on Locke because he wasn't special, but Jack's passing words of "don't give up on him," kept him going. So far everyone had a purpose but Jack, and his is now established.
Next, the translation will be posted soon on this site:
http://lostpedia.wikia.com/wiki/The_Incident,_Parts_1_&_2 . I would check tomorrow or Friday, but I can guarantee it'll be there soon.
Juliet dying was horrible. I loved the development of this character and how she actually was able to guide Sawyer. Her death was definitely a sad moment.
The actual nuke was an interesting thing. Miles brought up an excellent point that being "what if the nuke IS the incident?" It likely killed everyone around the blast zone, but being so far underground, it may not have. As Sayid said in season 2 when they were in the hatch and he was asked about the concrete, and he responded "I have only seen concrete this thick at Chernobyl" (paraphrased). Concrete can seal in radiation leaks, so this idea is DEFINITELY a possibility, but whatever happens, it'll change the show as Damon Lindelof had said.
And finally, the big one - who the **** was that guy? Locke's character became so different this season. When he spoke to Richard, he was pretty hostile, but I never for a second guessed that the man we thought was Locke was not. So, it seems the island has the ability to create ageless people as seen with this man (whatever he is), Jacob, and Richard. I never thought that Locke really died in Season 4 nor did I think his body would be in the case. I made a joke that this was the second season that lock was shown dead at the end.
All in all, ****, this year will suck.