I am curently writing a script and it starts out light, kind of a coming of age drama, but by the end of the second act it gets much darker, almost to the point of a thriller.  Is that something that can be pulled off without jerking the audience around.  It's not like from dusk till dawn where the whole genre switches, but it starts off very low key, then goes into very dark waters. The closest movie I can think of that does this is this movie I saw on tv not to long ago called something wild, are there any other scripts on this site that are kind of like what I described?  I don't want this script to be one of thsese "lets throw the audience for a loop", I just want to make it as real as possible.

Without knowing exactly what you mean without seeing the screenplay, If it's not like from dusk till dawn, the only examples I could think of off the top of my head, Psycho? Misery? The Dead Zone? The Green Mile changed it's tone constantly throughout. Signs? The Village? Donnie Darko? The Vanishing? Reservoir Dogs? Are any of those close to what you mean? I've never seen Something Wild. Personally, I like when movies blur the lines between genres. It adds originality to it, and keeps the screenplay exciting whenever you have new elements being introduced.

well it's nothing like what you mentioned, like, it's not like this story goes off into violence, I think there will be a little, but nothing horrific, Maybe more like the truman show, How it starts off light hearted, but once it reaches the halfway point it gets darker.  The story I am working on gets much darker than that, but it starts off kind of in the same feel, eventhough they are two totaly different types of films.

The War of the Roses is like what you're talking about. The Witches and Edward Scissorhands as well.

I think I understand what you mean and my advice is this... As long as the change is gradual, I think you can pull off a change in tone, although I believe you mean a change in genre. In any case, whether the change is sudden or drawn out, I think it should make sense within the context of the story. In From Dusk Till Dawn, it didn't. It was simply "let there be vampires." Dreamcatcher is another example in which it didn't work. The transition from buddy movie to horror, which was sudden, was excellently carried IMO but the transition from horror to action to sci-fi reduced the movie to a jumbled mess. It worked in the book but not the movie. Personally, I don't think there's anything wrong with a sudden change in genre though. Curveballs like that, though extreme, usually make films more interesting for me though not all the time. But for what you're doing, I suggest a gradual change. That's my advice. Hope it helps.

One example of a movie that changed mid-stream is War of the Worlds. This one gets mixed reviews for what it did because it begins as an action-adventure film with the attack and the family setting out to get the kids home. Somewhere in the middle, the movie shifts to a thriller where they are hiding in the house. They stay in this house a long time and encounter the aliens and have some intense moments. This is a turn around from the first part of the film, and though I had no problem with it, mixed reviews show that some people did. The film moved from this thriller section back into the action movie and that's how it finished. The momentum between action and thriller is a huge difference and it's based on conventions of the genre. The house part was suspenseful and Spielberg does know what he's doing to get the right effect, but you'd been set up to that point with a story-action formula, so to get keel-hauled into a character-driven suspense thriller in the midst of it all is quite a jerk.

Another film that has a mixed tone is Corpse Bride. Horrific imagery blended with a romantic comedy. Holy cow. This one didn't change gears, it was like this for the whole film. I didn't know what to think of it and I still don't. I think I liked it, but it messed with my head too much to know for sure.

So when you want to switch, be careful doing so. Genres are there to gear films to a specific audience. Some of us watch a little of everything and can easily appreciate a genre shift in the middle of the film, and even appreciate it to an extent. Others will hate it because it's not what they came to see.

Thanks you guys.  The story gets darker as it moves along, like not till the halfway mark, well at least in my outline it;s in the halfway mark.  Like I want it to be up beat, then when certain events happen it takes a downward spiral.  I will look into what everyone said, seems like some good stuff there.  thanks again.

PS: has anyone seen something wild, if you haven't you should check it out

From your first post in this thread, it seems you may be confusing tone with PLOT.

To use your example:  From Dust Till Dawn starts off as story about a pair of killers evading the law...then switches to a vampire/monster flick.  This is a change in plot.  BUT, both plots have the same tone -- violent, blackly humorous and horrific (yes, even the first story with the Gecko brothers is horrific).

Might be a bit nit-picky, but I thought I'd point it out.

That's true, Lon. The tone never really changes much in FDTD and that's how it's able to switch genres halfway through from typical Tarantino crime action into a horror movie and have a natural feel to it.

The movie Click is exactly what your talking about.  The beginning of the film is a light-hearted comedy, but at the end it turns into a serious drama.  Maybe not as dark as you want it to be, but it was a good change.  The transition was pretty gradual from the second to third act, but once it changed it changed hard.  I honestly wouldn't be surprised if some of the actors get awards for their performances in that third act of the film, because it seriously was a 180 degree turn.  I never thought I would ever see people tearing up at an Adam Sandler movie, but they did.  The very end brought it back to the comedy realm, but man that was a serious genre change in that film.    

Yeah, my friend saw Click and she said it was sad. I was kind of confused because I thought it was a comedy. I guess I understand now.

The concept by itself isn't automatically bad, but if you don't do it right it could be awkward.  If used well, though, it can be powerful.  
A random idea I've floated through my head for ages is one that starts out a romantic comedy, but eventually the protagonist would get hit by a car.  The idea would be that the car accident would be completely unexpected and we would have learned to bond with the protagonist by then.  I started it by realizing that in the modern genre distinction we either never bond with the character or we don't have those kinds of horrific jolts - whilst life has all genres except sci-fi.
My point is, don't worry about something unusual; unusual often equals original.

Btw, in H.G. Wells' novel The War of The Worlds there is also a large bulk where the protagonist spends three days hiding in a house.  But that doesn't feel odd.  What does is that the second half of the book has a different protagonist dealing with the calamity differently.

The Sixth Sense changed from horror/thriller to melodrama when the kid decided he was going to help all the dead people, like the girl with the video camera. The problem here is that, in the process of changing tone, the ghosts are revealed as posing no threat at all. Therefore, the first half of the film is a total lie.