I thought it was a great ending, even though i didn't understand completely until today. The blog below helped me.
I wonder if we'll ever see any of these actors again?
http://watching-tv.ew.com/2010/05/24/lost-series-finale-review/
If there was any big surprise last night, it was how overtly Christian in its imagery and message the series proved to be. Its heavily underscored lesson was that everyone was forgiven — that word was used over and over. And the water at the Magic Glowing Source was used for the purposes of transubstantiation: “Drink this,” Jack was told upon being handed water, a phrase later repeated when Jack gave water to Hugo. Given the liquid’s effect particularly on Jack, the dialogue might just as well have quoted directly from a Communion service: “Drink this, for this is my body which is given unto you. Do this, in remembrance of me.”
For if there was one thing we can probably all agree upon, in the end, Jack Shephard was a Christ figure whose sacrifice saved many other people. The imagery could not have been more specific: Jack’s questioning and obeying of his father; his leadership of a small group of disciples; his final ascension (in TV terms, in a glowing white light). Even the piercing of his side by Locke/Man In Black was in the part of his body where Christ was speared while in agony on the crucifying cross.
But for most of its long but rarely boring length, the final Lost did not huff and puff and labor toward a heavy metaphorical conclusion. Instead, it was, well, pretty delightful, full of reunions that were both emotional and funny (how about that re-meet-cute between Sawyer and Juliet at the vending machine?). There were sweet little jokes, such as when, 90 minutes into a two-and-a-half-hour show, someone said, “It sure don’t feel like it’s over.” I don’t know how it’ll play with hardcore Losties, but I was glad to see a fan favorite such as Hurley not only avoid great suffering, but become the most important assistant in Jack’s glorification. Hurley was always the most lovable character in Lost, and it turned out that if he represented anything, it was Love itself.
The metaphor that had been used weeks earlier, about the cork in a wine bottle that kept evil from escaping — that was dramatized well, when Desmond first uncorked the island and it did indeed look as though Evil had been loosed upon the island world. Then it had to be, er, re-corked by Jack, to refute Evil’s pronouncement that “you died for nothing.” Quite the opposite: Jack died so that everyone could gather in the Church of the Sideways and have a splendid wrap-party of the soul.