Continuity mistake: When Jack speaks to Michael and Jin, as they build the raft, and then when he walks up the beach and inquires about Sawyer's trouble with his head, the backpack that Jack carries on his back is nylon, black/green with white trim. Yet, when Sawyer asks, "Sensitivity to light, that bad?" the backpack is suddenly transformed into solid black leather, of an entirely different style. Then, in following shots it jumps back and forth. (00:16:40)
Deliberate mistake: As Ray drives the pickup truck, an oncoming vehicle beeps and the marshal heads behind Ray's pickup. In the shot through the cab's rear window facing the bed, as the marshal pulls behind, the bed's side wall interior is seen (note the metal loop tie down on top) and the entire tailgate is gone; yet the tailgate is intact later, when the pickup flips over. The tailgate was removed for the shot to allow visibility of the marshal's vehicle.
Continuity mistake: When the marshal and Ray drive their vehicles down the long road, the endless line of telephone poles are on their left as they drive, with barren land on their right. However, when they pass the third vehicle the poles are on their right and then repeatedly change sides in the following shots. (This has nothing to do with camera angles.) (00:30:10)
Visible crew/equipment: While Jin is cuffed to the wreckage, Sun points to her wrist and explains in Korean, but Sayid shouts, "The cuffs stay on!" At the start of the next shot, a crewmember's arm is seen holding the reflector screen to Sawyer's left, as he makes a sarcastic comment. (00:09:30)
Continuity mistake: When Sawyer shoots "Sawyer" there is a 15 ft tall grounded lamppost at the corner of the link fence, with an overhead curved head giving off the dramatic spot of light in the wet darkness, near the trash receptacle. However, earlier when Sawyer gets out of the car at the Sweet Shrimp, as he checks his gun, that towering lamppost is non-existent. (00:25:55 - 00:36:10)
Continuity mistake: When Kate finds the pilot's wingpin in the mud, the pilot's reflection is seen in the water as he lies on the branches above Kate. When Jack approaches they all look up and in the overhead shot the pilot's position differs and he lies on different parts of the branches, note their shape.
Continuity mistake: Jin is handcuffed in season 1, "House of the Rising Sun" and the cuff remains on his left wrist until season 2, "What Kate Did" when Locke removes it. The handcuffs have a distinctive shape - a single strand connected via pivot to a double strand with the lock area. When Jin is initially cuffed to the plane wreckage, the single strand faces out at his wrist, but in following shots, in this and all the subsequent episodes, the handcuff actually switches sides repeatedly, going round his wrist the opposite way.
Continuity mistake: After Jin is pulled off Michael, when Sawyer removes the marshal's handcuffs from his pocket there is a very short link chain dangling - about a couple of inches. However, when Jin is cuffed to the wreckage the link chain is considerably longer - about a foot. (00:06:15)
Other mistake: The Monster appearing in the pilot and causing the turbine to explode is a mistake (not trivia). This is actually an artefact of poor CGI effects that was left in the show in error. It was confirmed by the producers. You can see it best here: http://www.lostpedia.com/wiki/Image:Turbine_Explosion.gif.
Revealing mistake: With Marshal Mars in pursuit, as Ray drives his pickup, he holds the steering wheel with his left hand, and his stiff prosthetic right arm is down at his side. When Kate grabs for the steering wheel, in the side exterior shot the stunt driver is quite noticeable, as he grips and turns the steering wheel with his good right hand/arm. (00:30:40)
Continuity mistake: On the airplane, the same passengers are seen in numerous shots with different main characters, and purportedly Kate and Marshal Mars (row 25) are in the same cabin on the opposite side of Jack, Rose and Locke (rows 23 & 24), yet are not seen in shots where they should be seen - though in shots of Jack and Rose, during the turbulance, the same woman and man (behind Locke) fly up as in the Kate and marshal shot. Some examples: When Kate and the marshal are shown during the turbulance, note the red-haired man with the black shirt beside the marshal and other men behind, and in one shot of Kate and the marshal, a woman and man both fly up to the ceiling of the cabin. In some shots of the turbulance, when the red-haired man is seen, the marshal and Kate are gone, replaced by other passengers. Just before the tail section breaks off, men behind the red-haired guy have either changed seats or disappeared, and so forth. Row numbers seen on the luggage compartments overhead are inconsistent with passenger seating. Such as when the tail section breaks off, the man is pulled out from row 26, yet the number above reads 13, or when Claire boards the numbers overhead are 20, 21, 22, yet Jack is in row 23, which is the second row behind the wall. The interiors of the Oceanic airplane also significantly differ in various shots. One example - the seats on the airplane have blue square velcro coverings on the passengers' seat headrests, and long, wide magazine racks on the divider wall behind Locke, but when they carry Locke onto the airplane, they don't exist.
Continuity mistake: When Jack, Charlie and Kate are walking through the woods and Jack is holding the transceiver, Charlie ask if he hears anything. Jack then answers "You keep asking if there's anything", while holding the transceiver with his right hand and his left hand down. When it cuts he holds on to the transceiver with both hands. (00:00:20)