The movie originally ended with Caesar's yell of "That day is upon you NOW!" and the apes beating Governor Breck to death despite Mr. MacDonald's plea. Poor testing resulted in the addition of Lisa yelling "NO!", which was followed by repeated footage of Caesar's speech dubbed by Roddy McDowall
to make him reconsider his decision and give the film a more hopeful tone. See more
(at around 1h 11 mins) When the apes rise up against the humans, shortly after an ape throws a flaming torch to start a fire, the camera pans back and for a brief moment you can see a metal tube mounted to the ground shooting gas to create the wall of fire. See more
The King is dead. Long live the King! Tell me Breck, before you die - how do we differ from the dogs and cats that you and your kind used to love? Why did you turn us from pets into slaves?
Because your kind were once our ancestors. Because man was born of apes, and there's still an ape curled up inside of every man. You're the beast in us that we have to whip into submission. You're the savage that we need to shackle in chains. You taint us, Caesar. You poison our guts. When we hate you, we're...