First off, thanks very much Nate, for taking the time to do such a good analysis.

In my humble opinion, tone is something that's easy to mess up, especially when you're starting out. I recall an example from that site Scriptshadow, where one of the reviewers, in discussing tone, recounted a story of how in one of his first scripts, he ruined a tender moment between a guy and the girl he just got the courage to ask out by immediately having the guy turn around and run into a tree. He now realizes how it totally jumbled the tone of the script, and marked him as an amateur.
Now I'm not claiming to be Tonemaster Flash or anything, but I try to be very aware of how everything I put into the script changes that oh-so-delicate factor of tone.

CJ, "delicate" is an apt choice of words. Even with a bombastic action movie or an edgy thriller, a writer has to maintain a delicate balance throughout to create a coherent and consistent tone.

To me, so much of it goes back to something Nate mentions in the OP: Narrative Voice. It's the resonance of a writer's style tied to the story's genre. Tone arises from that invisible character -- the story's Narrative Voice -- as they 'tell' the story through scene description, scene construction, transitions, and all the other multitude of choices we make in crafting the narrative.

@CJ: You're very welcome! Thanks for the support, much appreciated.

Haha I know exactly what review you're talking about. Yeah, and I think that's a great point. As movie-going audiences get smarter and smarter, I think a fluctuating tone in your movie is one of the easiest things for an audience to innately pick up on. They might not call it that, but if you polled people after a movie like Jennifer's Body, I bet you a lot of them would have said something like "It was weird. It couldn't figure out what kind of movie it was."

And if that's the general movie-goers picking up on that sort of thing, it makes you realize how important it is to have that locked down before you're sending your script off to be read by someone who might have read literally thousands of scripts.

@Scott: I was thinking about it while I was writing the article, but one of the biggest hurdles for amateur writers who have given me scripts to read is that they haven't quite found their own narrative voice. I think that comes mostly from not having written enough scripts. I don't think a polished and personal narrative voice just erupts in a first screenplay--it's a matter of getting comfortable with the way you tell stories.

And to take that one step further, your narrative voice goes with you on every script you write: the tone of that script is how you're adapting your voice to fit whatever genre you're writing in. The tighter your tone, the more consistent it is, the better the read and eventually, the better the film.

Nate, thank you for putting in the time to breakdown this Spielberg event. I saw the entire video after reading your first post and your analysis takes it to another level. Very helpful for us newbies.

What a great read, thank you so much, Nate. I look forward to your next post.

Gabe and Atlanta: Thank you guys! Very much. It's great to hear that people are reading these and liking them--means a lot. Thanks for the support :). Part 3 should be coming in the very near future.

I know this is an older post but I thought of a movie that had tone problems: Hancock. One minute it's goofy, the next minute gory, serious and dire, then ridiculous again. Its tone was all over the place, and I think that may have led to the vague feeling that something was "off" with it, though many moviegoers probably wouldn't be able to identify just what was wrong. It was the tone.

Age before beauty, I always say.

And you're spot on with Hancock. Text-book tone schizophrenia. Like you said, the audience probably couldn't put their finger on the exact term for it, but they definitely know when a movie starts out as one thing, switches to another thing, and ends as a third thing. And they dooo not like that.