Narc

Narc is a 2002 crime film written and directed by Joe Carnahan, starring Jason Patric and Ray Liotta.

Undercover narcotics officer Nick Tellis (Jason Patric) pursues a drug dealer after his cover has been blown, ending in the death of the drug dealer, as well as a stray bullet causing the miscarriage of a pregnant woman. Eighteen months later, Tellis is persuaded to investigate the cold-blooded murder of another undercover narcotics officer named Michael Calvess. He is partnered with another detective, Henry Oak (Ray Liotta). Nick Tellis tries to seek out the real reason for Michael Calvess's death behind his partner's back, and we are given a glimpse into the seedy side of police work in a poorer area.

The film was well received, and made back twice its fairly modest production cost.

Tropes used in Narc include:

Bittersweet Ending: Tellis finally get's told the truth of how Calvess died during Oak's last moments of life, and it was all recorded on tape. He is left to choose whether he will give the tape to the police or not. The credits roll before he make's a choice.
Black and Gray Morality
Boom! Headshot!: The dead body they find in a bath tub had his head obliterated from a shotgun blast.
Chase Scene: The film starts off with a very dramatic and powerful one with Tellis and a drug dealer.
Cluster F-Bomb
Darkened Building Shootout
Dirty Cop: Both Henry Oak and Tellis are this, but especially Oak: "The only thing you need to know about me, is that I'm gonna bag the motherfuckers that killed Mike. If that means breaking every point of procedure, then they're broke."
Flash Back: There are many flashbacks to Calvess's death, some of them come from Tellis's imagination whilst other's are showing potential scenarios of what really happened in that tunnel.
Friendly Fire: In the aforementioned chase scene, Tellis takes the risk of firing a number of shots whilst running when the drug dealer he's chasing takes a baby hostage. The drug dealer is killed instantly, but one of the other bullet ricochets and hit's a pregnant women.
Gang-Bangers: Deacon, and Darnell and his buddy.
Gangsta Style: Tellis holds his gun this way after being taken by surprise for a couple of shots, and hits nothing. He then holds the gun normally and with his second hand for support and manages to shoot Darnell in the leg. It's done out of desperation and as a knee jerk reaction, rather than trying to look cool.
I Just Shot Marvin in the Face: Tellis and Oak investigate a grisly scene with a headless corpse holding a shotgun in a bath tub. We find out that it wasn't a suicide, but an accidental discharge because the man was trying to use the shotgun as a smoking pipe and forgot it was loaded.
Internal Affairs: Oak initially questions Tellis, making sure that he's not with Internal Affairs.
Jack Bauer Interrogation Technique: When Oak and Tellis find the two guys that beat up Calvess in the tunnel, they are tied down to chairs and get increasingly worse treatment. Oak ends up punching both of them a lot of times and firing a revolver close to their heads.
Jerkass: Both Nick Tellis and Henry Oak themselves.
Let Me Tell You a Story: Through casual conversation, Oak ends up telling the story of his wife's death to Tellis, and how he's ever since he's had no reservation in breaking the rules
No-Holds-Barred Beatdown: Oak beats up a criminal with an eight ball inside a sock after he's been arrested. Oak also beats up Tellis when he begins to suspect him and challenge him. Not to mention what the beating Calvess get's before he dies.
Only a Flesh Wound: Tellis get's lucky when he's shot bt Deacon, it results in a relatively minor neck wound. He still has to go to hospital and take medication though.
Redemption Quest: Tellis's girlfriend accuses his obsession with the Calvess case to be this.
Sliding Scale of Shiny Versus Gritty: Far, far on the gritty side. Narc focuses a lot on rough and poverty stricken areas.
Sliding Scale of Idealism Versus Cynicism: This is a cold and cynical movie.