Bookish Staten Island high-school senior Vee (the promising young Emma Roberts, doing her best) is about to have a night to remember. After a number of disappointments -- she learns that her mother can't afford to send her to the college of her choice, her crush spurns her, and her best friend Syd (Emily Meade) pisses her off -- she decides to sign up for a mysterious online game that has gone viral. "Nerve" then gives her the option of either being a watcher or a player: Watchers assign dares to the players, who receive cash deposits into their bank accounts when they successfully complete the challenges. Eager to prove to both herself and Syd (who has become a star within the game) that she has a spontaneous side, Vee chooses to be a player. The all-seeing eye of the watchers pairs her up with a stranger named Ian (Dave Franco, clearly way too old to be playing a teenager) after they meet cute in a diner, and as the crowd-sourced dares ramp up in intensity and payoff, most of the other players are quickly eliminated. Soon, Vee and Ian are challenging Syd's spot in the rankings, as well as that of another Nerve veteran named Ty (Colson Baker, aka rapper Machine Gun Kelly, who's apparently reading his lines off of cue cards). Revelations about Ian and the game itself cause the stakes to escalate even further, eventually threatening to derail Vee's life as she becomes immersed in this thrill-seeking adventure.Directing duo Ariel Schulman and Henry Joost (probably best known for the 2010 doc Catfish) inject a sense of humor and some decent action scenes into this techno-thriller. But screenwriter Jessica Sharzer, adapting author Jeanne Ryan's 2012 YA novel, never steps back to ask why any of these characters are doing the things they're doing. Does Vee want the cash to help her single mom (a criminally underutilized Juliette Lewis) and pay for her own tuition for art school? Or is she just playing the game to spite her socialite BFF and hang out with a guy who owns a motorcycle? Everyone's motivations are cloudy at best, and the script only deals in certainties when it depicts teenagers who will sacrifice anything for momentary digital celebrity.Cinematographer Michael Simmonds deserves credit for dressing up identifiable New York City landmarks in a rich neon glow, and for skillfully integrating a great deal of footage from iPhones and GoPro cameras into the narrative. Schulman and Joost clearly understand how millennials interact and are able to translate that nuance to the screen; it's just that they don't know, or can't articulate, what there is to say about it. Nerve ham-fistedly tries to warn us about the dangers of online anonymity and this generation's smartphone obsession by giving poor Roberts an eye-roller of a screed in the final third, which she delivers in a Colosseum-esque setting full of ski-mask-clad watchers (guess the NYPD had the night off). Although its first two-thirds are promising, the movie is eventually sunk by its cobbled-together premise and the filmmakers' inability to deliver an appropriate payoff -- instead, they wrap things up by resorting to entry-level nonsense about hackers and paranoia of the deep web.Is this reviewer thinking too hard about a summer teen thriller that's centered on a viral game of "truth or dare, minus the truth?" Maybe, but that doesn't change the fact that this movie breezes over or simply forgets a number of seemingly crucial plot points, or that it's full of undeveloped background characters who are suddenly revealed to be vitally important to the story. The filmmakers seem aware of these failings, but they were apparently convinced that audiences would be too impressed by the high-wire action scenes and digital noise to notice such details. Nerve ultimately feels a little sophomoric, and that's a shame: This movie could have been a cult favorite if it had told its story with more confidence and focus.