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.