From the “TV Squad” recap:
Visually, It was appropriate that Jack made his way back to the exact place he awoke on the Island, passing one of the tennis shoes his father was wearing in the casket, and even had Vincent by his side when we had our closing shot of his eye closing, rather than opening. While there are a lot of unanswered questions, we are supposedly promised additional scenes (about 20 minutes of them) on the DVD set that will answer yet more of them, as well as other answers given by the creators.
Ha! Now you have to pay to figure out what exactly happened. No doubt this burst of commerce will figure into the White House “jobs saved or created” calculations.