First off, a warning. This film is not told in your standard narrative style of having the story told from start to end. I can't figure out why teenagers were chuckling at it, because it's one of the many ways to keep you in suspense as the details slowly get pieced together, with each part of the puzzle from the vantage point of 8 individuals being joined at one point or another, without which there wouldn't be any whodunnit element, and too many jump cuts from one POV to the other in one single timeline. So there's nothing really amusing about it.
That said, you would've gathered from the trailer that this is about an assassination attempt on the life of US President Ashton, played by William Hurt, and the pieces of evidence that different characters have depending on their points of view - innocent bystander, television crew, perpetrators and of course, the US Secret Service, led by Dennis Quaid's Thomas Barnes and Matthew Fox's Kent Taylor.
I've always maintained Dennis Quaid as your alternative to Harrison Ford, and here, he takes on a Clint Eastwood like role in being part of the President's detail who has taken a bullet for him, and is now back on active duty. But while he's given top billing in the movie, the movie's divided quite evenly amongst the rest of the cast, save for perhaps Sigourney Weaver as a television news producer. While each individual thread contributed to enriching the story as a whole, I thought that Forest Whitaker's POV was one of the weakest, and brings back memories of Cloverfield's designated cameraman role in wanting to capture the "moment" for all and sundry to see.
It also dwelled a bit on American arrogance, where if the movie is to be believed, then the Secret Service has quite a lot of clout to be blazing their guns opening fire amongst sections of crowds, so long as the big man is down - whatever it takes to bring in / take down those whom they believe are involved in the assassination. What I had wanted to see from the suggestion of the trailer was that car chase scene where Quaid's car got smashed from the side, and no doubt it's been a while since I've seen an exhilerating chase sequence from an action movie of late. Kudos to the stunt team here in having 2 mid-sized saloons weave through crowded streets of vehicles and people, and totally let it rip into utter mayhem.
One thing's for sure though, that the "bad guys" aren't always as dumb as we'd like them to be. Case in point already through recent incidents at home, and underestimating, lulling into complacency and predictability are three of the worst enemies any protective detail could succumb toward. Of course the screenwriters here have it all planned out to make everyone look smart, and at the end of the day, in crafting a hero out of the situation. But that's just movie-land. Recommended for action movie junkies to tide through the temporary dearth these days, and for that chase sequence which was worth every minute of it.