Revealing mistake: When the boys are racing away on their bicycles from the Feds, the stunt doubles for Elliott and his friends are obviously way too tall to be children.
Revealing mistake: When Elliot, Michael, and E.T. arrive at the park after escaping the scientists, a ramp can be seen where they drive over the curb.
Revealing mistake: The silhouette of the mime wearing the E.T. gloves can be seen through the railing when Elliot is luring E.T. with the Reese's Pieces.
Revealing mistake: In the opening chase scene where E.T. is running back to the ship you can see the cart that E.T. is on when it is the side shot of E.T. and to left there is a gap in the plants and you see part of the cart.
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.
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)
Revealing mistake: Right before the government agent car skids out at the bottom of the hill, tire tracks from a previous take can be seen on the pavement. (01:40:45)
Revealing mistake: Elliot takes his dishes to the sink, opens the faucet and steam rises all over the kitchen. When the camera pulls back, one can notice that the huge cloud of steam is coming from somewhere along the window, not from the narrow stream of water from the faucet.
Revealing mistake: During the scene in the woods with the communication machine, Elliot tells E.T. that they need to go. You see the machine still working at a regular interval because a rope is pulling it. The shot pans to the left a touch and the rope stops moving, as if the person pulling it realises it's no longer in the shot.
Revealing mistake: When the boys' bicycles lift off they cast no shadow on the police cars nor on the road below.
Revealing mistake: When ET is grabbing things from the fridge, in the close-up his fingers swap from thin and long to chubby and short, obviously a puppeteer's glove.
Revealing mistake: After Gertie says she doesn't like ET's feet, Elliot scolds her and she mouths his lines.
Chosen answer: They actually are smoking and there are cigarettes on the table.
Mike K