A video game trope where, after defeating a boss, there is a cutscene showing The Hero delivering a final blow. Sometimes the boss battle will end when the boss has a tiny sliver of health left to justify it. This may be seen as a way to avoid Critical Existence Failure, by implying that the enemy's health bar/Hit Points were to show how close you were to sufficiently weakening it to the point where the attack can be delivered. This does not cover incidences where a cutscene shows a boss dying or ignores the fact you just kicked its arse after the fight, but it can still be a form of Story Overwrite if the finishing blow is the exact same attack that you used dozens of time in the actual battle (if it's so efficient, why didn't it work the first time(s) you used it ?). Bonus points if a player character consistently delivers the final blow in the same manner after every boss fight.
Compare: Limit Break and Finishing Move, which follow the same function, but are delivered as part of normal gameplay, rather than a cutscene. The two can meet halfway in "Press X to Not Die".
Asura's Wrath has these usually at the end of each boss or mini boss encounter (And after each burst), with the added bonus of doing a surprisingly skippable QTE (Though there are exceptions and not pressing those lowers your score).
In Zone of the Enders: The 2nd Runner, after Dingo defeats Nohman in Anubis while inside Aumaan at the end of the game, followed by a cutscene in which Nohman reveals that he killed Dingo's comrades before, the player can finish off Nohman by either obliterating him or by slashing him.
The ending of The Legend of Zelda: The Wind Waker shows Link ramming his sword into Ganondorf's head and fusing with the power of the triforce to turn him to stone for all eternity (or until they decide they need him for a Windwaker-verse game again).
In Gravity Rush, when you whittle down a boss's health bar, you're told to "finish them" by tapping a crosshair that appears on their weak point, causing a cutscene where Kat attacks them with what appears to be a powered up version of the Spiraling Claw. This is subverted in your first battle with Raven; she does the same move to counter it and sends Kat flying back.
Made even more powerful due to the fact that the cut-scene ends and forces players to deliver the coup de grace themselves
That same situation is subverted in the first Metal Gear Solid when Grey Fox is pinned to the wall by Metal Gear Rex and asks Snake to Mercy Kill him. No matter how many times the player pushes the fire button, Snake can't bring himself to do it.
Beat 'em up
Played straight in Devil May Cry; every time you land the "kill" shot on a boss, the game immediately switches to a cutscene, usually involving Dante finishing off the boss (or in Nero's case, trying to go for the kill but being foiled by Villain Exit Stage Left). Needless to say, this doesn't happen during the inevitable Boss Rush, or the Bloody Palace.
Done with every boss in Bayonetta. Bayonetta summons a giant demon to finish the bosses off.
Gungrave ends with Grave holding a gun on the Big Bad. He doesn't fire until you press the Fire button. Very satisfying.
Don't forget Grave's boss fatality shots, the Graveyard Special. Get a boss to about 15-20% health, and the Demolition Shot gauge starts blinking. Pressing the triangle button switches to a scene of a graveyard where Grave pulls off a flashy coffin attack that finishes the boss off.
In the second game, during the end stages, depleting a major boss' life meter blurs the screen to a cutscene of your character (out of three) finishing the boss off with an exaggerated version of one of their high-level/max level Demolition Shots. In the case of Grave vs. Fangoram, Grave uses at least four of his D. Shots in one combo. And a vanity pause.
In Legend Of Success Joe, when Joe wins a match, a poorly animated instant replay of the finishing blow is shown on the screen above the ring.
Soul Calibur IV, at least for some character's stories. Others just show the Big Bad dying, etc.
In Punch-Out!! for the Wii, exactly one of the special cutscenes triggered by finishing the opponent with a Star Punch (or under certain other circumstances) features Little Mac delivering additional punches that finally send the opponent to the canvas.
This is how enemies are shown defeated in in Infinity Blade, with special cutscenes if the enemy is on a ledge.
Every boss in the original three episodes of Duke Nukem 3D is finished in a cutscene. The first takes a shotgun blast to the skull. The third and final boss has his eye kicked through an American football goal. The second boss however has his head ripped off and his neck shat in. Literally.
After defeating the final boss in Perfect Dark, the cutscene shows Joanna shooting off a shard from an altar which impales the boss.
Inverted with Halo: Reach's epilogue, "Lone Wolf", where Noble Six recieves a coup de grāce from a squad of Elites after being defeated.
After the fight with Primagen in Turok 2, the Energy Totems, if you saved them all, fire off beams to finish him off.
The first part of the ending cut scene in Super Mario Galaxy where Mario punches Bowser hard enough just after the final attack to send him into the surface of a star.
Portal 2 does this for the Final Boss. Your last portal shot puts it in a very inconvenient position, but it claims to be able to recover even from that until GLaDOS punts it into deep space and rescues you.
In Banjo-Kazooie, not only is the coup de grace done in a cutscene, it's not even Banjo or Kazooie who directly delivers it; the player's last relevant action is to release the Jinjonator, who defeats Gruntilda in a cutscene shortly afterward.
Also subverted in the third Mega Man Zero game. The final boss seems to be fine after being defeated and knocks Zero down, but Zero gets some help and the player then receives control for one last unmissable attack.
In Donkey Kong Country Returns, this happens twice with bosses. Once after you deliver the final blow to whatever critter the Tiki of the world is possessing, and one where he punches out that Tiki. You can even add extra hits to that Tiki if you're patient enough.
Iji's fight against Annihilator Iosa ends when you disable her nanoshield. Then (unless you were pacifist) Iji puts her gun at Iosa's head, the screen fades to black, and a shot is heard.
I Wanna Be the Guy inverts the trope: if you get hit with a specific move of Kraidgief's, it turns into a ridiculously epic piledriver with Fist of the North Star music playing in the background. This is pretty blatant overkill, as just touching Kraidgief is more than enough to kill The Kid.
Real Time Strategy
Used in Overlord II with the overlord jumping on and slicing open every boss after you've sufficiently drained its health bar.
Age of Mythology ends its campaign with a showdown between the allies of the gods, led by the recently-glorified Arkantos, and the allies of the Titans, led by a giant animated statue of Poseidon. Bringing down the statue in-game is depicted in-cutscene with the end of an epic duel between the two.
Even if you manage to kill the statue without using Arkantos.
Role Playing Game
In the first part of The Legend of Dragoon, every boss battle ends with Dart lunging at the boss to finish them. This is subverted a few times. Ulroborus, which wasn't quite dead after the attack; secondly, Kongol who swats Dart out of the air mid jump; finally, Lloyd, who is unexpectedly shielded by Sister Wink. In the Barrens, it's because of this that Mappi is able to steal his Dragoon spirit.
Subverted in Kingdom Hearts II; in the final boss battle, after warding off an extremely prolongedattack, a small cutscene shows shit going down and blows being delivered. However, at the end of all this he is not dead; just left with 1 HP and permanently stunned, allowing you to deliver the final blow.
Subverted in Final Fantasy Crystal Chronicles - the first one: when the Miasma Core is down to a sliver of health, you're transported to Raem, the true final boss. Once you defeat it, you're warped back to the Miasma Core where you finish the job.
Oddly subverted in Fire Emblem: Radiant Dawn. There's a cutscene showing Ike and Yune charging up their final attack, but the attack itself uses the game's normal battle animations (although Ike's killing blow is always one of his Critical Hit animations.) Once the blow is struck, it switches back to CGI for the final cutscene.
Furthermore, the attack is still subject to all of the usual rules of the RNG. If the cutscene doesn't trigger, then you know before it happens that Ike's attack is about to miss.
Pretty much every boss fight in NieR does this using scaled-up versions of the Sealed Verse powers.
In Dragon Age: Origins the Bosses got one, this also randomly occurs after dealing the critical hit as sort of automated Finishing Move on smaller Mobs or a Boss recurring as normal Mob (like Ogres).
A rather spectacular one happens occurs at the end of the fight with the Archdemon, wherein a character grabs a nearby fallen sword to finish it off in dramatic fashion. This can variably be the PC or various party members depending on how you handle a number of earlier story decisions. Potentially a Crowning Moment of Funny if it happens to be your staff-wielding Mage of a Warden who is normally too physically weak to even equip a sword.
In Fable: The Lost Chapters, if you take the evil path toward the ending of the game you end up fighting The Guildmaster, The Obi-Wan and father figure of the series. After bashing your way through a deluge of guardsmen he confronts you with a cutscene asking you one last time to take the good path, and allow him to teleport you to that quest, if you say no he starts to say something along the lines of "Well, fine. But don't think you have me beat I still have a trick or--" you then brutally beat him to death in cut scene. That is basically the closest the game comes to a Kick the Dog moment.
In Deus Ex: Human Revolution, the battle against Jaron Namir concludes with Adam giving the boss an extremely satisfying haymaker to the jaw. A fitting payback for what the monster did to you early in the game.
Happens for quite a few bosses in Vanquish, odd thing is occasionally they combine it with a Quite Time Events so what might become a Coup De Grace could blow up in your face forcing you to fight another mode of the boss or start all over again.
Very common in the Super Robot Wars series. Defeating important villains at the appropriate point in the plot will almost always prompt a cutscene in which they get some HP back and then get killed by the attack that defeated them in their respective show. Sometimes justified, as with GaoGaiGar's villains, since only Guy can pull out their Zonder Cores.
This was sometimes subverted in some games or cases, like the aforementioned Robeast coring in Super Robot Wars W, if you dealt the finishing blow with the relevent attack in the first place.
Wide Open Sandbox
Optionally used with certain targets in Grand Theft Auto IV with the introduction of the executions. When faced with a target who either pleads for their life or just stands and talks trash while awaiting death, the player can either just kill them however they want or switch to a handgun, target them, and pull the trigger to begin a short cutscene that shows the protagonist killing his target. Executions range from simple "Shoot him in da head" to "Plenty of blood and pain". Some examples are:
Vlad: Vlad begins threatening Niko, who places a pistol against his forehead, turns his head and covers his eyes to avoid the blood spray, and pulls the trigger.
Darko: Niko shoots him twelve times, one for each friend lost in the war because of him, and Darko still has enough time to thank Niko for putting him out of his misery before expiring.
Faustin: Faustin tells Niko that Dmitri will betray him (very true), but Niko shoots Faustin in the knee, then in the chest, causing him to fall off the roof, bounce of the awning of his own club, and splat onto the street.
Dimitri: If you take the Revenge path in the game, Niko will shoot through a boatyard and small tanker to get to him. The first shot goes to the nuts, and while Dimitri is holding his leaking tanker, Niko headshots him about two seconds later.
Pegorino: Unlike the other examples, the player has no choice of whether or not to kill him. After taking him down in regular combat, the cutscene shows Pegorino on the ground, ranting and coughing up blood, before Niko shoots him in the head with an AK-47.
Ray Bulgarin: After fighting through mobs of henchmen aboard Bulgarin's plane, Luis confronts him in the cockpit. When Bulgarin pulls a grenade, Luis shoots him and parachutes from the plane as it explodes.
Used for the defeat of every rival gang boss in the Saints Row games.
The Elder Scrolls V: Skyrim sometimes has randomly-triggered finishing move cutscenes when you defeat enemies; there are a number of different ones depending on how you did it (with a weapon, unarmed combat, Shield Bash, whatever). Originally, these were only available if you killed an enemy with a melee attack (because of the Ludicrous Gibs potential), but later patches added in coup de grāce cutscenes for bows and magical projectile attacks as well.
In Time Crisis 4. You, and possibly a second player, are armed with machine guns, grenade launchers, etc. For the whole fight, you shoot the boss while he wrestles with your ally. Once his health bar is low, it goes into a cutscene where the NPC finishes the boss off mano-a-mano.