Revealing mistake: In the scene where David starts the game with Joshua, it asks him what side he wants to be (1 for the U.S. and 2 for USSR). Look carefully at the closeup of the computer screen - his choice, 2, appears long before David actually presses the key.
Revealing mistake: Where the officer is pushing the buttons on the wall panel to launch the missiles, on the both occasions you see it, the panel buckles highlighting the flimsy set.
Revealing mistake: On the large screen at the end of the film, Joshua and Prof. Falken are 'writing' to each other. Falken types in "Hello Joshua"- he not only says it, but you can hear him typing it as well, however, on the screen, only the word "Hello" appears; the word "Joshua" doesn't.
Revealing mistake: When Joshua/WOPR is trying to figure out the launch code at the end of the movie it picks the "1" out of the 1704 twice.
Revealing mistake: When David begins to play against the WOPR computer, the images on the war room screens show various tactical movements by other countries. These are the same images shown the first time the war room is seen.
Answer: Writer Walter Parkes explained they had John Wood read the dialog backwards to give it a flat tone (i.e. Game a play to like you would). Then after rearranging it they would synthesize and process it to give it an electronic quality.
Bishop73