In the movie Split Second, Harley Stone (played by Rutger Hauer) is a cop who often flouts the rules working in a decaying, flooded London circa 2008 (clearly an alternate timeline), as global warming has caused sea levels to rise.A supernatural killer that Stone is convinced exists has returned, and it's his mission to find the killer before anyone else dies. Unfortunately, his boss doesn't think he's stable enough to work without an assigned partner, Dick Durkin. Hilarity (and action-adventure) ensues.
And Show It to You: In the climax, Stone pulls out the monster's heart from its chest and blows it to smithereens with his gun. Interesting that it might not be overkill: the monster doesn't drop until the heart is destroyed.
BFG: Dick Durkin snaps and ends up demanding, literally, Bigger Fucking Guns. Big, Big Fucking guns, in fact. To the point where, when browsing the police armoury, he dismisses several weapons as 'Too fucking small', including an A3 Assault Rifle and an R1 Grenade Launcher (!)
By-the-Book Cop: Dick Durkin is much more mindful of proper police procedure and much calmer than Stone due to his past education on killers and psychopaths. Subverted towards the end when he realizes that they're up against a supernatural monstrosity and he becomes just as gun-happy as Stone.
Connect the Deaths: The monster kills its victims in specific places in order to draw a dot-to-dot version of an astrological symbol on the city map.
Cowboy Cop: Stone is a complete rundown of the trope: He's a multiple gun-toting hardass who treats everyone like crap, shoots first and asks questions later, pisses off Da Chief and treats his by-the-book partner like a nuisance and gets the job done with superior firepower.
Cynicism Catalyst: In a flashback it's shown how Stone was fairly well-composed before his partner was killed by the monster he has since been pursuing. Stone blamed himself (especially because he was having an affair with his partner's wife) and became a paranoid, rude gunslinger in response.
Da Chief: Chief Thrasher (Yes, really), who spends most of his time trying to rein the violent and snarky Harley Stone in.
Finger in the Mail: A long-vanished Serial Killer returns and taunts the protagonist by sending him a metal briefcase that turns out to contain the heart of the first new victim packed in ice with a very large bite taken out of it.
Non-Appearing Title: The film seems to be called Split Second because that sounds cool. It has nothing to do with anything that happens in the film.
Although to be fair, Harley and Dick versus The Giant Demonic Mutant Rat in Futuretown was probably already taken.
Plot Hole: It is likely that the identity of the Serial Killer as being a giant Xenomorph-like monster was decided on fairly late in production, because a lot of the movie becomes nonsensical as a result. The alien is a nine-foot tall behemoth, yet no one in the night club noticed it walking around, while there's also a Murderer P.O.V. shot shown at human eye level. It has giant claws, yet it can smear big letters on a mirror in blood. It can't talk, but somehow it paid someone to deliver a victim's heart to the police station. And so on.
Psychic Powers: Stone has a mysterious psychic connection to the killer; he can predict where he first strikes upon his return and sense his presence by hearing the killer's beating heart. Dick Durkin thinks it's because he's a Scorpio.
Serial Killer: Stone is pursuing a serial killer who cuts out his victims' hearts to eat them and has a personal vendetta with Stone. Subverted in that it turns out it is actually a giant monster with unexplained motives for killing people, although presumably intelligent.
Shape Shifter: Heavily hinted at, although never explicitly shown. The Killer is mentioned as having "Multiple Restriction Polymorphic DNA Strands", which include the DNA of all the people it has attacked and killed, plus rat DNA. It can do things which shouldn't be possible for a creature of its size and appearance (See Plot Hole). Most glaringly, walking through a crowded nightclub and into a well-lit toilet to attack one of its victims.
Possibly to avoid Special Effect Failure - if a film states that a creature is a shapeshifter, the audience will reasonably expect to see it change shape on-screen at some point. The budget presumably wouldn't have supported this.
Skeptic No Longer: Detective Dick Durkin refuses to believe that the Serial Killer he and Harley Stone (his partner) are tracking isn't actually a human being at all, but rather some kind of monster. And then he runs face-to-face with the thing.
Stone: Did you see him?
Durkin: That wasn't a him, that was a fucking it!
Seeing the monster also leads to Durkin's line (and temporal Madness Mantra), "We need to get bigger guns!", which under the circumstances was a very rational reaction.
Trailers Always Spoil: The creature isn't revealed as such until near the end of the film - before that, it is only fleetingly glimpsed and its attacks usually take place off-screen. So you wouldn't know that it wasn't a human, but rather a giant Xenomorph, Rat-Hybrid monster...Unless you'd seen the poster at the top of the page, which is also the box art on some releases of the film.
We All Live in America: The English characters use American names for objects and British Police procedure seems to be identical to American.
Durkin: I followed him down an alleyway - he shot a trash can!
You Dirty Rat: Despite not looking or acting like a rat, the creature is described as having Rat DNA, and one character who comes face-to-face with it calls it a 'Rat Bastard' before taking a shot at it.