"It's bold in terms of jerking people around. I may have gone too far in a few places."
The hour-long "making of" footage also includes Ben Burtt, the movie's film editor, who criticised the film's pace.
"In a space of about 90 seconds, you go from lamenting the death of a hero to escape to slightly comedic with Jar Jar to Anakin returning ... It's a lot in a very short time," Burtt said.
The footage captured Rick McCallum, the film's producer, watching the film with "his hand over his mouth" in shock.
"It boggles the mind," Lucas said.
"I have thought about this quite a bit, and the tricky part is you almost can't take any of those pieces out of it now, because each one takes you to the next place. And you can't jump because you don't know where you are."
After the audience left the screening, the footage shows Lucas, McCallum and Burtt in a "slightly heated exchange", the Hollywood Reporter reports.
"I do a particular kind of movie of which this is consistent," Lucas said.
"But it is a very hard movie to follow. But, at the same time, I have done it a little more extremely than I have done it in the past.
"It's stylistically designed to be that way, and you can't undo that, but we can diminish the effects of it. We can slow it down a little bit, so if it's intense for us, a regular person is going to go nuts."
The film was not a hit with Star Wars fans.
The news comes as a production designer for Star Wars: The Last Jedi revealed Lucas wasn't happy when he went backstage to look at how Episode VIII was being made.
Star Wars: The Last Jedi's production designer, Rick Heinrichs, told the Hollywood Reporter the legend of the franchise personally came to tour the set at London's Pinewood Studios.
Heinrichs described Lucas as a "cranky guy" who was not a fan of the number of sets being built for the shooting of the sci-fi blockbuster.
Heinrichs recalled that The Last Jedi director Rian Johnson had about 160 sets in his original script.
He described it as "ridiculous".
"I didn't say that to Rian, because I figured on something this big he'll find that out on his own. It's a 100-day shooting schedule," he told the Hollywood Reporter.
"So there's more than one set a day you have to prepare for."
In the end, the production of the film had 125 sets on 14 stages at the studio.
Heinrichs said Lucas' original thinking played a part in their decision to reduce the number of sets they were making.
He recalled how they tried to "hew to the original mandate that George Lucas had; treat it as if it's a documentary somewhere out in space, so you really believe this is happening".
"That's one of the appeals of Star Wars, that it's not this endless world-building place," he said.
"There's a very grounded aspect to it and they always tried to find a place that's connected to our world."
When Lucas toured the studio, Heinrichs said he made his strong opinion known.
Heinrichs said: "We went into Star Wars saying we're going to do matte paintings and we're going to be hanging miniatures. That's the way we're going to do this 'cause that's what George would want.
"And of course George visited and he's like, 'Why are you building all these sets?' 'Well, because that's what you like, isn't it?'"
He added: "He's a cranky guy but his point is that for the big stuff, obviously planets, spaceships flying, when you're not close enough to see actors in it, there isn't much point any more in actually building something."
Despite this, Lucas told Johnson he was highly impressed by The Last Jedi and said it was "beautifully made".
