I'm not very good with disaster fiction. I tend to find it immensely difficult to read, because, well, I love humanity and I don't really want it to disappear. So the first few tens of pages of The 5th Wave, describing an alien invasion of Earth involving (for reasons best known to the aliens) four "waves" of attacks - EMPs, massive tsunamis, plague, humans who aren't really humans - and a general end to Life As We Know It, was quite profoundly disturbing. Yancey does a good job of creating this horrifying world in which the apocalypse is actually happening, here and now, where there are people who remember what the world was like before, and where no-one can trust anyone any more. Humanity's last gasp.
Then Hot Evan Walker trundles into the story and The 5th Wave descends into the comfortingly trite territory of "mind-numbingly stupid YA romance".
Cassie (short for Cassiopeia), our heroine, who up until page 150 seems perfectly sane for a sixteen-year-old whose world has just exploded around her, is shot by a Silencer, an alien who's disguised as a human; she's rescued by Hot Evan, who, I kid you not, takes her to a frickin' farmhouse where they sit around drinking hot chocolate and nattering about the good old days while the world crumbles around them. Now, Cassie knows there's something odd going on with Hot Evan, but she doesn't actually do anything about it, for reasons. Instead, she lets him come with her to save her brother from an alien death camp where they're training child soldiers -
The EMPs, tsunamis, plague I can understand (even if I'm not utterly convinced by their scientific viability). The Silencers are at least faintly plausible, if a little inefficient. But I feel that human child soldiers stray into the realm of fantasy somewhat.
Anyway. Back to the Cassie/Hot Evan saga. Cassie discovers that Hot Evan is actually a Silencer and an alien, but that's okay because he's hot. And kisses her when she says "Don't kiss me". (Seriously, Evan? Not cool.) And, incidentally, he can help her get into Alien Death Camp.
This happens. Cassie kills some people, then meets up with an old crush, and more YA romance-type stuff happens. I sense an impending love triangle. Snooze. Hot Evan appears to save the day at the last moment, muttering something melodramatic about choosing between humanity and aliens, and ends up heroically blowing himself up while Cassie and her crush (with little brother in tow) drive off into the sunset (literally).
In summary, The 5th Wave is total and complete hokum. It's dull, it doesn't make sense, and Hot Evan annoys me. Give me The Hunger Games any day.