There's a tendency among first-time screenwriters to not have faith in the openings of their scripts. They're told to grab the audience from the start, but often first-time writers have a hard time beginning their story with an strong opening scene. My gut is that a lot of this has to do with early writers placing too much emphasis on backstory and exposition. Usually the audience needs a lot less exposition than the writer assumes.
In any event, it seems like an unwinable paradox to Mr. First Timer. They wonder,"How can I write an opening scene that will get an audience excited if they don't know anything about these characters?" Often, they'll go for a trick that J.J. Abrams both used effectively and beat into the ground - open the script with a scene from the climax, then flashback and tell the story of how things got to this high point.
As a reader, I find this trick usually has the opposite effect. When I see it deployed, I heave a heavy sigh because I now know exactly where this script is going and usually I'm going to have to sit through another 100 pages before the characters catch up to me. A good writer might be able to make the journey to this point interesting... but I think you can guess how often Mr. First Timer makes that work.
I'm sorry to say that even Abrams overindulged in this gag. It was a trick that was really effective once on Alias, during the Super Bowl episode. At the time, the low-rated show was hoping to pull in viewers who felt that the show's plots were often too complicated and inaccessible. So what did they do? They put Jennifer Garner in black lingerie and had her strut in front of the camera. It was a typical set-up for the show. She had to go undercover as a prostitute in order to get access to a crucial agent in the enemy camp. After a scene showcasing Garner in two separate sexy outfits, which lead to an action scene where the plane she's in loses pressure, the episode flashed back 24 hours.
The trick here is that despite the eye candy both Garner and the action provided, there were very few plot twists exposed in this opening scene. The audience didn't know why Garner was on this mission, what she was after, who this guy was, or really anything. As the episode progresses, it's soon exposed that this mission is the key to bringing down the entire enemy agency. However, J.J. didn't give that twist away in the opening. There was still something for the audience to be surprised by later. Jennifer Garner in lingerie was just the bait.
In other words, if you're using a non-chronological structure to get the audience hooked early on, make sure you're just baiting the hook - not dumping your whole supply of worms into the lake. I feel this sort of gimmick is overused anyway, but if you're determined to use it, use it well.
But before you open your film with a scene from late in the story, ask yourself it is absolutely necessary and if it's an asset to the story you're telling.
2 weeks ago