The Aloner: All of the protagonists qualify, at some point or another.
Alone in a Crowd: Turns into this for Zac, when the other two begin to grow closer to each other and exclude him (at least from his point of view.)
Apocalypse How: Very close to a Class 4, although a very tiny fraction of humans and other beasts manage to survive; vegetation is left largely untouched. Since the extinction event is apparently a cyclical event that will happen over and over again, eventually the world will be completely empty, making it a theoretical Class 5 after enough repetitions.
Big Fancy House: Zac lives in one for a while, once he realizes it's time to "move up in the world."
Book Ends: The film begins with a slow shot of a sunrise. The film ends with, well, a planetrise - yeah, that enormous ringed world on the cover finally makes its appearance in the film's closing shot.
Chekhov's Gun: Zac uses a remote-control system to control a lawnmower at one point in the film. At the end, he suggests using it to deliver a truck full of explosives to a site. Ultimately subverted, however; Zac ends up delivering the payload himself.
Conflict Ball: Api's apparently holding this when he tells Joanne why he and his best mate had been fighting. The way he phrases it seems to be meant only to cause a conflict between himself and Joanne and prompt a fight that Zac unwittingly is pulled into. If he'd told the whole truth, all of that could've been avoided.
Cover Drop: The picture on the front of the box? It's not just artwork; it's the ending of the film. Whether or not this spoils the ending is up to the viewer - the scene really has no bearing on the plot.
Cosy Catastrophe: At first Zac has a relatively easy time coping with the end of the world - drinking champagne in a huge mansion, filled with paintings and other finery that he collected himself.
Good Times Montage: Zac gets one early on, as he enjoys all of the pleasures that the empty world has to offer, including playing with both train sets and real trains and driving a new car through a shopping mall, and decorating a mansion with as many pieces of fine and expensive art that he can find. It gets worse, though, as the emptiness of it all and his own guilt over causing it starts getting to him.
Insane Equals Violent: Zac's rampage once he snaps involves him threatening a life-sized crucifix with a shotgun as he rails at God, then destroying buildings with construction vehicles.
Love Triangle: Between Api, Joanne and Zac. They are the only known people left on Earth, so it's not surprising.
Minimalist Cast: The credits list a whopping six actors for the entire movie. Half of those only appear in brief flashbacks or recordings.
My Greatest Failure: Zac feels responsible for the results of Project Flashlight, because he didn't challenge data that he felt was incomplete and chose to try to kill himself instead. It's unclear whether or not he could have made a difference if he had spoken up. Still, he spends much of the second half of the film trying to track the effect and find a way to prevent a second one.
New Era Speech: A passionate and teary example is made by Zac Hobson - resplendent in his chemise - from the balcony of his new mansion to an audience of cardboard cutouts and a combined background music/applause track.
No Name Given: Only Zac Hobson is given a surname. There are a handful of other named characters (Joanne and Api, as well as a corpse named Perrin that Zac holds a brief, one-sided conversation with) whose last names are never given in the film.
Playing Against Type: Bruno Lawrence was known for playing working-class roughs; he does a good job as a quiet, introverted, tormented scientist, but it isn't a role he would've been expected to play.
Rage Against the Heavens: Zac bursts into a church screaming, "If you don't come out, I'll shoot the kid!" The kid being a life-sized crucifix.
Sanity Slippage: The first third of the film shows Zac's slow descent into madness.
Scenery Porn: The countryside is almost a character in itself.
Scenery Gorn: There are quite a few scenes of the destruction that would be caused by the disappearance of mankind as well, including an airplane crash.
Sole Surviving Scientist: Zac Hobson, a scientist who was working on Project Flashlight. A malfunction caused almost everyone on Earth to simply disappear. He goes a little crazy in the first part of the movie, but after meeting two other survivors he tries to destroy the laboratory where the experiment took place so it can't happen again.
Survivors Guilt: Zac gets this in spades. Api and Joanne as well, although not nearly as much.
Token Minority: Considering the film's premise, Api may well be the only Maori (or non-white person period, for that matter) left in the world.
Title Drop: during Zac's crazed speech at the cutouts of political figures.