Continuity mistake: When E.T. Is at home with the speak and spell, the back cover is missing as he is working on it. In the next shot, the back cover is on it again.
Audio problem: When E.T. is home alone using the Speak & Spell for the first time, he types in E at one point, but the electronic voice can be heard saying F instead. (00:46:10)
Continuity mistake: While ET is watching Mary read the story of Peter Pan to Gertie, in the shot from outside the closet we see Elliott using his left hand to close the shutter slats, but in the next shot inside the closet it is Elliott's right hand closing the slats.
Continuity mistake: When Mary gets her first look at an ailing E.T. lying on the bathroom floor, she panics then hurries everyone downstairs - leaving E.T. behind. Moments later one of the astronauts happens upon E.T. and now a bright pink bath towel can be seen draped over the bathtub's edge, which wasn't even there to begin with. (01:16:00 - 01:17:55)
Other mistake: When Elliot and ET finally meet in the backyard at night, ET returns some of the candy that Elliot had left for him. In the shot before ET places the candy before Elliot, we see him standing with all his fingers extended, so he is definitely not holding any candy in his hands. He is also not wearing clothes, so he has no pockets. Where was ET keeping the candy before giving it back to Elliot?
Continuity mistake: In the scene on Trick-or-Treat night, Elliot and E.T. go to the forest so that E.T. can set up his communication device to "phone home". While they are there, Elliot is appealing to E.T. for him to stay, saying he will get used to it. While he is talking to E.T. he is inches away from his face. But in the very next shot it shows E.T. looking around, staring into space, with Elliot nowhere to be seen. But the next shot shows Elliot is in E.T.'s face again just as he was two shots before.
Revealing mistake: In the original 1982 version of the film when Elliot and his friends fly away from the police on their bikes, look closely and you can see that their bikes have no handlebars.
Continuity mistake: When Elliot opens the solar system book, ET's finger is on the edge of the page. A frame later it's several inches above.
Other mistake: When ET walks to the fridge, there's a shot of Elliott's classroom with the camera moving towards him. Watch the chubby kid on the right, who can't help staring at the camera for a brief second. (00:44:15)
Revealing mistake: On Halloween when the kids are getting ready to go trick-or-treating, Mary tells them to return one hour after sundown. But as E.T. turns around to look at her, human legs are visible below his ghost outfit. (01:02:30)
Continuity mistake: After Elliot frees the frog, notice a group of kids in the background with a blonde girl in a blue dress on the left: they're either watching Elliot in awe, or looking down at their books. This changes back and forth several times.
Continuity mistake: When Elliot burps, the pencil on his desk disappears between shots. Also, the paper swaps from laying on the edge to several centimeters away.
Continuity mistake: Throughout the movie E.T.'s fingers are shown to be very long, thin, and boney. But in the final scene, when Elliot and E.T. are saying goodbye, E.T. reaches down to pick up the flower pot to take with him. The camera shows his hands picking up the flower pot but they appear the size of human hands wearing gloves, not the long skinny fingered hands we saw during the entire movie.
Factual error: Unbelievable that for 30 years no one has pointed out that in every shot with the moon, except when the moon is full, the crescent is pointing the wrong direction. In the evening (ordering pizza), in the Northern Hemisphere (California), a crescent moon will always be pointing down to your right (the bright side will be on the lower right). The only time it could point the way it does in these scenes is in the wee hours of the morning, at 4 or 5 a.m. and looking to the East. Spielberg didn't even fix it in the re-release.
Suggested correction: Actually the problem with moon scenes that we see a crescending moonphase (less than a quarter) when Elliott first meet E.T. After that in a couple of days there is a full moon which could be reached in about 16-17 days from that phase which we saw first. It would be also about 11 days if the first shot was mirrored and actually was an increasing moonphase. But the whole story is about 6 days long. So a full moon couldn't be reached from a quarter of moon.
Factual error: The government operatives go to great lengths to cordon-off and sanitize Elliott's home with extensive hazardous material preparation. Controlled airflow, Hazmat suits and everything. But as soon as E.T. "dies," everybody takes off their Hazmat masks. So, E.T. was only a Hazmat threat when he was alive? A real government Hazmat team would never drop their guard like this, as long as the alien body was still present.
Continuity mistake: When Elliot's mom leaves to school and Gertie says ET can talk, the cupboard behind her swaps from lit to unlit between shots.
Visible crew/equipment: When Elliot is luring ET with Reeces Pieces and goes into his room and through his drawers to find more candy, you can see the shadow of the crew moving on the wall next to Elliot.
Continuity mistake: When Keys turns around to see what's rustling in the bushes behind him, his flashlight swaps hands between frames. (00:05:50)
Continuity mistake: When Elliot opens the book with the solar system, the book pages are folded, yet a frame later, from a different angle, the book is opened wide.
Continuity mistake: When Gertie replies she's going to Elliot's room, she swaps from holding her trolley with one hand to two.