So they obviously get off The Island at some point... But when they do, do they go back in time? Or did they change time? Unless Jack is totally nuts - which is a possibility - or his father is still alive... Or maybe he just thinks that and nobody is bothering to tell him otherwise?
Also, where are Penny's guys? Remember Season 2 finale? We saw that she had a couple of dudes looking for Desmond, they get a reading on their equipment about some "Magnetic Anomaly" or something and they get pretty worked up and call Penny and say "It's us. I think we found it." So if Naomi and her crew are working for someone else where have Penny's dudes been all this time? We saw Penny in real time (supposedly) when she was chatting with Charlie (R.I.P.)...
So many questions and a whole Summer to wonder...