In the opener, Jack leads the survivors up the coastline with the water on everyone's right, jungle on the left. After the commercial break, they are still walking, but now it's reversed, with the ocean on everyone's left.
When Bonnie goes to call Ben, in the first shot the door is wide open. After the angle changes, the door is closed and she has to open it.
When Sarah is talking to Jack in the hospital, the bandage on Jack's head changes size.
In the opening scene with Jack on the plane, he reaches for the newspaper with his left hand. As the shot changes, he picks it up with his right hand.
As Jack is leading the group to the radio tower, Naomi asks him what he used to do for a living. She would have known he was a doctor, as he had been treating her as she recovered from the punctured lung she received parachuting onto the island. However, that's exactly why she replies "Of course you were," as she realizes she knew already.
When Charlie hits Desmond with the oar on the boat, it's daytime. Charlie dives to the underwater station and is captured. Ben learns about it and sends Mikhail to sort things out, who says he can be at the underwater station "by dawn". When Desmond wakes up, it's daytime again and Mikhail is shooting at him, which means that Desmond had been unconscious all night. His boat, however, was not carried away by the waves.
Even if Desmond were conscious it would be difficult to stay in the same place without the boat drifting. As they made a weight belt for Charlie out of stones, it's possible they made an anchor that way, too, though there's no evidence of this.
Even if Desmond were conscious it would be difficult to stay in the same place without the boat drifting. As they made a weight belt for Charlie out of stones, it's possible they made an anchor that way, too, though there's no evidence of this.
Throughout this episode, on the island, Jack has salt/pepper stubble and there are patches of gray stubble below his sideburns and along is lower jaws. In the "real world" scenes Jack has a full beard, and it is all black, there's no gray at all in his beard.