When Barry boards the flight to Hawaii, he wears the blue suit with the red tie he wears throughout most of the film. When he is shown sitting in his seat talking to the man next to him, his tie is yellow. The next scene, showing him leaving the Hawaii Airport, he wears the red tie again.
When Barry is looking at the piano after he brought it into the office; Lance arrives and he runs to greet him. When Lance and Barry go back to office; all the lights are on, in what had been a dark office.
After the brothers smash into Barry's car and it stops spinning, blood trickles from Lena's scalp and onto her cheek. When Barry returns to the car after beating up the brothers, there is no blood on Lena's face.
When Barry punches the wall under the map, the map is stuck inside the hole. Later, there is a quick shot of him in front of the map again where you can see the hole above the map, but in the next shot, the map is clearly still stuck inside the hole.
When Barry is watching Lena walk away after she drops off her car, he is holding his coffee thermos "backwards" (the handle is pointing away from his palm). After the cut when we see him duck inside the garage, he is holding the thermos by the handle.
When Barry calls Lena from the phone booth in Hawaii, a red light dot is reflected in the side of the phone booth. Some think this is from the camera, however, professional film cameras don't have such a light. It appears to be the traffic light from across the street.