Although we don't see much of it, the main character in 21 gets caught counting cards by security chief Williams and suffers a pretty convincing beating while tied to a chair. He also hints that he'll "put a hammer to the side of his face, then kill him", as honest as a sinner on trial, if he ever gets catches him again.
100 Feet contains a fatal beatdown of the protagonist's Love Interest by her husband's ghost. Towards the end, the ghost's face becomes visible because it's been headbutting the guy so hard that it's gotten drenched in his blood.
In one point in Alien: Resurrection, Purvis delivers one to Dr. Wren, before killing him with a chestburster.
Brick reaches its climax with the forces of Tug and the Pin shooting it out (and with the cops, when they arrive), and Tug violating the truce that they'd met under by savagely beating the Pin to death with his bare hands. All that is actually seen is Tug's fist flying in the dark, and Pin's screams and pleas for help. The Pin is frail and physically disabled in some way, and Tug is a heavily muscled bruiser, making this a horribly one-sided fight.
In one of the final scenes in Casino, Nicky Santoro (Joe Pesci) and his brother Dominick set up a meeting in a cornfield after things have calmed down with the Mafia. Unfortunately, the bosses are still upset about the role Nicky played in the collapse of their Vegas operation; so, Nicky and Dom are met by a gang of thugs who proceed to beat Dominick to a bloody pulp while making Nicky watch, and toss him into a freshly-dug grave. They then proceed to do the same thing (and worse - at one point, it looks like they cave Nicky's skull in) before tossing him into the same grave and burying them alive.
Cherrybomb: During the film's crescendo, Crilly beats Malachy to a bloody pulp. Luke then leaps to Malachy's defence and beats Crilly over the head with a metal bar, ultimately killing him.
In The Dark Knight Rises, Bane beats the hell out of Batman in their first encounter. At the end of the film, Batman repays the favor.
Dawn of the Planet of the Apes has Caesar deliver one to Koba, after Koba accuses him of loving humans more than apes, including his (Caesar's) children. Caesar barely restrains himself from going further.
For the scene in The Departed where Billy Costigan beats up the two Italian guys in the store.
Drive. The Driver is a pragmatic and vicious fighter, killing one man by stabbing him with a curtain rod. Then, while saying goodbye to his not-girlfriend, he kills a hitman with them in an elevator, going to even further extremes (doubtless his love was also his Berserk Button). She is shown to be visibly freaked out by the killing.
Also in Drunken Master, where his character Freddie Hung suffers a not only vicious but humiliating beat-down. He runs away from his master's painstaking (and slightly ridiculous) training, and stops to dry his clothes in an open hut. The owner of the hut—a notorious assassin named Thunderleg, as luck would have it—arrives, and beats Freddie up, ridicules his father, and otherwise utterly humiliates him, forcing him, in the end, to beg for mercy and run away.
At the climax of Event Horizon, the possessed Dr. Weir proceeds to beat Captain Miller to a pulp with his bare hands, finishing with a kick that snaps Miller's spine against a wall.
Stephen Chow in God of Cookery gets brutally beaten by the Eighteen Brassmen of Shaolin and dragged away in a trail of his own blood as a Running Gag. The humor comes from a mix of just how vicious the beating is combined with it happening repeatedly at unexpected moments.
In Halloween H20: Twenty Years Later, the villain endures a thoroughly over-the-top gauntlet of smackdown, culminating in being pinned between a large truck and a solid surface... and, when addressed, he looks up!
Liberally used by the Japanese in Ip Man. The film doesn't bother hiding its nationalism.
Two specific examples: Master Liu tries taking on three Japanese pugilists, only to find that Conservation of Ninjutsu is not in play, and ends up getting kicked around. Later on, Ip Man's fight against General Miura culminates in the latter getting pinned to a pole and getting beat down. An arguable Lampshade Hanging of the Curb-Stomp Battle/No-Holds-Barred Beatdown occurs when scenes of Ip's practice on a dummy are interposed with the thrashing.
The sequel has the Twister's horrible pummeling to death of Master Hung. When Ip pays him back, though regrettably not in full, no one objects.
Irreversible, which has a backwards plot, starts with one of the characters using a fire extinguisher to bash someone's head in.
Dave and Big Daddy are on the receiving end of one in the film's Darkest Hour; this example also crosses over into Cold-Blooded Torture as they were both tied up and helpless.
The fight between Hit Girl and Frank might also count after Hit Girl is knocked nearly unconscious and Frank continues to punch her (an 11-year old, no less) in the face savagely two more times.
In Kill Bill, The Bride receives a hell of a beating at the hands of her former partners in the incident that kicks off her Roaring Rampage of Revenge, though it's only shown in brief moments in flashback.
Johnny Weng beat the living crap out of Ah Jong's best friend Sidney in The Killer in a scene that was very much a Tear Jerker.
In The Kingdom, Action Girl Janet Mayes' final fight with the Giant Mook at the end of the movie definitely qualifies. Basically most of the fight has Mayes being slammed around the room by the Giant Mook, and Mayes retaliates by biting the Giant Mook's ear off, then shooting his leg, then stabbing him several times in the groin and the chest before finishing him off by stabbing him in the head. Ouch.
Also happens in Chow's Kung Fu Hustle, when the Beast gets really pissed over being brained by Chow.
Last Man Standing's beatdown of John Smith after the bad guys corner him without his guns in the bath in particular is inspired by the above beatdown of the Man With No Name in Fistful of Dollars. Which was itself taken from the beating received by Toshiro Mifune's Man With No Name in Yojimbo.
Morty delivers one to his former accomplice whose incompetence resulted in his being imprisoned for a decade for a crime he didn't commit. It's filmed from the victim's point of view!
The protagonist gets a brief but very efficient one from Gene before he has a chance to tell him that the reason he killed Jimmy was because Jimmy was a police informer who was planning on screwing them both over. For a little extra scary atmosphere, consider that the thing in the freezer that Gene was banging XXXX's face on was probably the Duke's frozen corpse.
In The Lion King 2, during Zira's first attack on Simba, several lions leap on him, maul him, knock him down a cliff, and then follow after him and maul him further. He survives, but he ends up collapsing from exhaustion after barely escaping.
Agent Smith does this to Morpheus in The Matrix prior to capturing him.
Jackie Chan ends up on the receiving end of this in the movie Mr. Nice Guy. He does end up getting his payback through the employment of a very large vehicle (at that time in Chan's movies, in lieu of having a final climactic showdown, Chan would just get in a very large vehicle and drive a hole through the bad guy's base.)
Near the end of the film The Ninth Configuration, Stacy Keach's character is having the stuffing beat out of him by a motorcycle gang. This is the moment that he remembers that he is not an army psychologist, but a deranged marine known as Killer Kane. Kane gets up and proceeds to deliver an epic, murderous unarmed beatdown to all the biker scum present.
Panic Room features a pretty gruesome beatdown, and leaves the guy almost completely incapable of walking, moving or speaking. It actually becomes quite funny later on, though, as he's tasked with so much stuff to do, when he probably couldn't even take a crap if he tried.
Castle's fight against Loonie Bin Jim, which happened right before this scene, is practically two of this tropes put next to each other: First, Castle gets kicked in a Dynamic Entry, then his enemy proceeds to kick him, bite him and dodge all of his punches, while telling him crazy things about kidney failure. Understandably, Castle is rather pissed after getting repeatedly kicked in the groin, so he throws Jim against a wall with enough force to nearly crash it, before beating him further up. Jim only manages to escape by throwing shards of glass in Frank's eyes.
The Purge: A scene early on in the film demonstrates a gang doing this to a person in a city.
In Return of the Jedi, Luke Skywalker nearly falls into The Dark Side by delivering one to Darth Vader, using his lightsaber like a baseball bat and chopping off his hand. Minutes later he receives one from Emperor Palpatine using ForceLightning.
Jackie Chan's character from Rumble in the Bronx gets a beatdown. A street gang corners him in a dead-end alley and proceeds to bombard him with glass bottles. Let's just say this scene was "bloody" and leave it at that.
Salvage has Duke Desmond delivering this to Claire Parker over and over again, as she keeps reliving her death at his hands.
In Saw II, Jigsaw, with cancerous brain trauma, takes a hard earned beating from Donnie Wahlberg.
The Shawshank Redemption features several of them, including the guards beating up an emotionally overwhelmed inmate who complained that he was not supposed to be there, ( said guard then left the inmate to die in the infirmary) and The Sisters routinely beating up Andy, and the guards beating up Bogs (one of The Sisters) so severely he ended up crippled for life. And that's just counting the ones shown on-screen. Red has a way of understating this in his monotone voiceover narration, which perhaps drives home the horror even more; this kind of thing is a commonplace occurrence:
Red:[after the guards retaliate] Two things never happened again after that. The Sisters never laid a finger on Andy again. And Boggs never walked again.
In Sin City, Hartigan beats Junior's head in until "all [he's] doing is pounding wet chunks of bone into the floorboards."
The first Spider-Man movie. The moment when the hero's at his lowest is the ideal time for a Crowning Moment of Awesome, but come on! Poor Pete's had half his mask torn grenaded off, a severely cut lip, a gash on his side, a black eye, on and on and on. When Spidey does his Heroic Second Wind, he delivers a beatdown to Goblin in return.
Spider-Man 3 has our hero getting a double beatdown from Venom and the Sandman. The way the fight was going, Spider-Man would've definitely been done for if not for Harry Osborn saving him in a Big Damn Heroes moment.
This happens to Sefton, a World War II POW in Stalag 17. The people who beat him were his fellow prisoners, who suspected him of collaborating with the Germans. (This action spurs Sefton towards finding the real collaborator, whom he glumly notes, probably "beat him the hardest.")
In the Stargate film The Ark of Truth, Mitchell gets one of these from the Replicator Merrick. Intercut with scenes of the Priors torturing Vala and Daniel and of Teal'c trying to get to Celestius with a hole in his back to up the violence level.
The Space Opera version of this happens in Star Trek II: The Wrath of Khan, when Khan springs a completely one-side ambush on the Enterprise, and blasts her so badly over several minutes that Kirk has to surrender in order to get a chance at his heroic comeback.
In the 2009 movie, Kirk gets one of these from Spock after he intentionally pisses him off, eventually going so far as to state he never loved his mother-who was just killed when Vulcan was destroyed not even a day ago.
And before that, Spock as a child had soundly beat the crap out of an older Vulcan boy for calling Spock's mother a whore.
Star Trek Into Darkness: basically, anyone who gets on the wrong side of Harrison gets one of these, until he gets on the wrong side of Spock.
A non-organic example: The Enterprise gets shot full of holes and turned into a smoking wreck by the Vengeance, a fellow Federation starship. Enterprise never got to fire a single shot back.
And in the game Stranglehold, Mr. Wong has his men beat the crap out of Tequila in a flashback after having intimidated Billie, Wong's daughter and the woman Tequila loved, into breaking up with him in a double-duty Kick the Dog moment.
Lex Luthor does this to Superman with the help of a kryptonite shiv in Superman Returns.
Happened to Raphael in the first Teenage Mutant Ninja Turtles movie, when a mob of Foot clan members take him down and then beat him into a coma. He only survives because the other Turtles are able to get him out of there and nurse him back to health (and this takes a long time). Several of the Foot Clan also wind up on the receiving end of this when the Turtles escape in the fight that ensues soon after said beatdown (the biggest fight in the movie thus far) and Tatsu proceeds to take out his rage on them for their failure. One of the Foot, a guy named Shinsho, is beaten into much the same state as Raph was for trying to stop him.
Godzilla ends up receiving one, which features long scenes of Mechagodzilla just throwing everything it has at Godzilla and King Caesar. Rather terrifying, even considering the dated special effects.
Mechagodzilla delivers one to Anguirus in the previous film as well, firmly establishing himself as a total bastard. Destoroyah, one of the most hated villains in Godzilla's Rogues Gallery, delivers one to Godzilla Junior, earning himself the ire of everyone who watched the film.
In the final fight scene of Mission: Impossible III, Owen Davian delivers one to Ethan Hunt. Then moments later, Ethan delivers one back to Davian.
In Thunderbolt, after Jackie Chan's character Foh puts a dangerous criminal in jail, Cougar gets out of jail and comes looking for him. Then Cougar, who'd previously murdered a man by dragging him behind a race car, took a construction crane and used it to wreck Foh's home and try to kill him, his father, and his sisters. The epic - and extremely bloody - beat-down ended with Cougar using the crane to pick up a metal storage shed that Foh was in - and flung him around inside like a pinball.
United 93's climactic end begins with a Zerg Rush of passengers surging forward towards the cockpit. The first terrorist to go down is pretty thoroughly Curb Stomped and beaten to death with a fire extinguisher.
Universal Soldier: Regeneration; The main villain played by U.F.C. Champion Andre "The Pitbull" Arlovski pulls this out IN SPADES. Rapid-fire punches? Check. Rapid-fire punches TO THE FACE? Check. Rapid-fire punches to the face that may be complemented with a protract-able blade from the lower arm upwards? Check.
In The Warriors, the first 10 minutes of the film shows a guy getting elbowed to death.
Watchmen expanded the Comedian's two page fight into a four minute borderline Gorn beatdown. Not only did the Comedian fail to land a single hit but it was set to Nat King Cole's rendition of "Unforgettable."
In Who Framed Roger Rabbit, Eddie Valiant during the final battle suffers several beatings from Judge Doom who, being a toon endowed with inhuman strength, tosses him around like a rag doll.
Wreck-It Ralph: Ralph is on the receiving end of one of these from a cy-bug morphed King Candy and it looks like it's all over as Ralph is forced to watch the demise of Sugar Rush until he gets a Heroic Second Wind and breaks free intending to sacrifice himself, knowing he can't beat King Candy in hand to hand combat.
Captain America: The Winter Soldier: After stopping Project Insight, Steve drops his shield into the water below, resolutely telling his opponent, Bucky, now the Winter Soldier, that he won't fight him — not anymore. The Winter Soldier, his memory returning and his mental state on the fritz ever since he saw Steve again, goes into Villainous Breakdown mode, confounded by such an action done on the basis of a friendship that he has no memory of. He then proceeds to beat the crap out of an unresisting Steve, shouting that Steve is his mission while doing so.
In Godzilla (2014), the M.U.T.O.s give Godzilla one when they double-teamed him, they gave him such a pounding that he fell over unconscious and they continued to beat on him some more. Prior to that, Godzilla was curbstomping each MUTO whenever they were going one on one.