The good news is that since the "Hunger Games" series of films, the young-adult (YA) action film genre is officially not only a thing, but also a Hollywood force to be reckoned with. The bad news is that not all YA movies are made equal, but the duds are still likely to spawn sequels.

"The 5th Wave" is one of those duds. Yes, there are some powerfully riveting moments and hordes of extremely watchable, athletic youngsters, but director J. Blakeson's film is a paint-by-numbers job that also leaves the ending, predictably, just hanging there. The initial reaction is "Huh?" swiftly followed by a mental calculation of when "The 5th Wave 2" (or maybe "The 6th Wave") will likely come out to tie up the loose ends.

For those suffering from "Hunger Games" or Jennifer Lawrence withdrawal symptoms, Cassie Sullivan, the heroine of "Wave" played by Chloe Grace Moretz, is not quite a satisfying substitute for Katniss. In fact she's a huge disappointment. Not that this is Moretz's fault — she does a very capable job given the material she has to work with — but alas, her lines (written by Susannah Grant, Akiva Goldsman and Jeff Pinkner) are plodding and uninspired, and the crucial action scenes are left mostly to the boys.