Background Music Override

""And of course the coolest part about the approach to Zanarkand is that the regular music is so awesome, they play the same music during the battles. No transition. None is needed. It's that cool.""

- Comment on Final Fantasy X's Crowning Music of Awesome page.

A video game trope, most seen in console RPGs.

In a game, there's generally separate Battle Theme Music and a Victory Theme. Then there's a Crowning Music of Awesome, which is so long that in order to hear all of it in one go, the player would have to sit around in the party-menu screen doing nothing. The developers don't want that to happen, so instead they let the Crowning Music of Awesome stay on during battles and victories and everything else. The music overrides all other normal themes for as long as the players are in the area or for the entire duration of the sequence. This ensures the player will remember the music as intrinsically tied to that scene, area, or sequence; the player sliced monsters in half to this music, they opened treasure chests to this music, they even saw the characters do a victory dance to it.

Alternately, in an intense situation, the battle theme or the regular boss theme plays during everything. It can be just as effective if the battle/boss theme is good enough.

Video Games

 * The most remembered instance in video game history would be the Ocean Palace from Chrono Trigger, where the ominous music kept going through the battles.
 * Chrono Trigger also did this much earlier in the game during Magus' Castle.
 * And after the Wham! Episode in 2300 AD (when you discover what Lavos is), "Chrono Trigger" starts playing... and plays until you leave the Storage Area, fights or no.
 * If you have in your party during the final battle against Queen Zeal, his theme plays instead.
 * In Disgaea 2: Cursed Memories, calling Kurtis or Axel with a cell phone will cause the music on the map to be replaced by their respective theme songs for the duration of the battle. Also, throughout the series, the Item World music changes whenever any pirates arrive on the scene, only ceasing once they've been dealt with, or if you move to the next floor.
 * The Final Fantasy series have many more instances of this.
 * FFIV plays the Boss Battle theme throughout the entire siege of Fabul, though your characters spend about as much time retreating further inward as they do fighting.
 * The After Years also plays the boss battle theme throughout the entire siege on Baron Castle; there are a couple of other instances as well with the Mysterious Girl's theme and the Archfiends' theme.
 * FFV has the Battle on the Big Bridge, the escape from Exdeath's castle takes you over the Big Bridge, which has many battles, but only one song, the awesomely, epic theme of Gilgamesh.
 * FFVI: The encounter with Kefka in Narshe where you split your party in three groups to defeat the incoming soldiers. "Protect the Espers!" is playing through everything up until the confrontation with Kefka himself.
 * In the scene where you team up with Moogles to protect Terra, Locke jumps down a hole, a bunch of Moogles decides to help, heroic music starts playing, you fight your way to boss, the music changes to the equally awesome "The Decisive Battle" as you get destroyed by the Marshal's Charge attack, then, as you prepare to try again with a better team, the music reverts. Yes, the music is just that awesome.
 * There's also minecart sequence where you're escaping from the Vector magitech laboratory, the sequence when you're trying to get to Ultros in order to stop him from ruining the opera, and the sequence where Sabin is holding up a house while you try to save the child inside. FFVI seems to like this trope A LOT.
 * Further, during the sequence where everyone is escaping from the falling Floating Continent, the battles continue "Metamorphosis".
 * FFVII: One of the two most prominent examples would be the Aerith Death scene, where Aerith's theme plays from Aerith being stabbed by Sephiroth, through the fight with Jenova-LIFE and until it's time to switch discs.
 * Much earlier, "Opening ~ Bombing Mission" is still playing during the first boss fight.
 * The battle theme version is done when you're climbing the section 7 Pillar. The regular battle theme plays through the entire climb.
 * There's also the Shinra HQ. After you break out, all you hear is "Trail of Blood", even during battles. Then, after the battle with Rufus, the game's normal boss battle music continues with the sequence with Rufus and as Cloud and Tifa make their escape.
 * To add to the list is the "Weapon Raid" Track, which plays whenever the Weapon's show up, and during the fights with them.
 * This also happens in one dungeon in Crisis Core, with its creepy slow-paced dungeon music.
 * Early in FFVIII, during the SeeD exam, "The Landing" plays from the start of the FMV sequence of the arrival at Dollet until you've reached your checkpoint at the central square.
 * FFIX: The most notable is "You Are Not Alone". The song plays while Zidane doubts himself and his right to live, and is considered by many an absolute masterpiece from the beginning of Zidane's black thoughts until his friends have made him see that he's not alone.
 * "Protecting My Devotion" is also pretty epic and memorable. It plays when you are defending the city of Alexandria from Kuja's monster invasion with Steiner, and the badass guest character Beatrix.
 * FFX: The stretch from the hill where Tidus tells his story, to the gates of the Zanarkand Ruins, plays "Fleeting Dream" (also known as Someday the Dream will End) continuously through battles.
 * In FFX2, "Yuna's Ballad" is used as the battle theme for Bahamut.
 * FFXIII sports the latest use of this trope in the series. It's used at least a couple of times throughout the game, most notably with the song "Dust to Dust" playing through the last Area of Pulse. In fact, Final Fantasy XIII absolutely loves to do this, and does it all the time, with themes such as "Defiers of Fate" and "Can't Catch a Break."
 * After the initial string of battles in FFXIII-2, the game allows "Full Steam Ahead" ("Dash" in Japan) play through on repeat until the first fight with Gogmagog. Of course, this song features a badass violin playing like a fucking guitar, and solos for every instrument. As with Final Fantasy XIII, XIII-2 is fond of this as well and uses it in a number of other instances and areas, such as A Dying World.
 * Used at least once in Chrono Cross, during the "save Marbule" quest, the Magical Dreamers music continues through battles.
 * It's also used during the battle with Miguel in the Dead Sea.
 * And in the beginning of the game we have a battle theme version, where the boss theme plays through almost the entire dream sequence (though without the chanting).
 * At the beginning of MARDEK, the "Mighty Heroes" track plays throughout the entire sequence up until the boss fight.
 * Also done in the arena. The battle music is never interrupted until the last fight, which is the only one that plays victory music.
 * Subverted in Star Ocean: The Second Story. When you beat Gabriel Celesta and finish the Cave of Trials, the "Star Ocean Forever" fanfare tune will start to play and will keep on playing as long as you stay in the cave. However, there won't be any enemy encounters until you exit the cave and come back (which will also reset the music). It's a swap but not an override.
 * In the Super Robot Wars games, player characters have a specific BGM that plays during the battle animations, however powerful enemy bosses will sometimes have their own BGM which will override the player characters' music.
 * In the first Super Robot Wars Original Generation game on the Game Boy Advance, a bug in the programming for an enemy boss which switches to the player's side prevented his BGM priority from being reset, making it so his music overrode all the other themes in the game, including the Final Boss theme. This has become known as "Trombe Override" after the name of the song, Trombe!. And has been added as a feature for every subsequent game in which that character appears.
 * In some climactic moments, a special theme, belonging to neither the players or the enemies will play throughout the stage, overriding both the player's and the boss's themes.
 * Of special note is the final battle of Alpha 3, where the heroic "GONG" plays for the entire fight...
 * In the third case of Phoenix Wright: Ace Attorney, the normal cross-examination music is overridden with the more intense "Pursuit ~ Cornered" theme, after a testimony flaw is pointed out by, allowing you to continue.
 * Played straight in Ace Attorney Investigations 1, where the "Presto" confrontation theme plays near the end of case two despite not actually cross-examining the killer, and Played for Laughs in the sequel, where Yumihiko Ichiyanagi's first argument is so overwrought and nonsensical that his extremely loopy theme music plays throughout it.
 * This carries over to Wright's playable appearance in Marvel vs. Capcom 3. His normal theme is a remix of first game's "Objection!", but once he reaches Turnabout Mode, the music automatically changes to a remix of the iconic "Pursuit ~ Cornered". This theme will override any other theme playing at the time, and it will only stop playing until either Turnabout Mode ends or Phoenix gets K.O.'d.
 * In a similar fashion to Wright's example in Marvel vs. Capcom 3, Bang Shishigami of BlazBlue fame can use a super attack once his Fuh-Rin-Ka-Zan meter is full, that overrides the battles theme song, changing it into "Beat a nail with your hammer"; although his never stops playing untill the match is over, as his Super Mode doesn't run out once it is activated.
 * In Cave Story's hidden final level, Sacred Grounds, the fanfares for Heart Containers and new weapons don't appear, so the track "Running Hell" plays uninterrupted until the Boss Rush.
 * Monster Hunter Tri Has three possible battle themes for each stage: The Great Jaggi/Baggi theme, each stage's normal Monster Battle theme, and the theme for the online-only nomad beast "Deviljho". Each overrides the themes before them (Jaggi<Stage<Deviljho).
 * In the beginning of Super Mario RPG, the standard battle music doesn't kick in until Mario is at Mario's Pad, until then, the overworld music just keeps playing.
 * Mega Man Star Force 3 had a particularly memorable bit where the WAZA HQ is under attack by clones. The Satella Police theme plays throughout, uninterrupted, until all the clones are dealt with. Unfortunately not repeated in the final stage, where touching the Crimson bits only plays the regular battle theme. Repeated in the post-game, where if an area contains an Omega Boss, a very special, dark and foreboding theme plays, not interrupting until you either leave or find the boss.
 * Dark Cloud had the Gallery of Time.
 * In Red Dead Redemption, "Far Away" upon landing in Mexico.
 * The PS2 Version of Tales of Symphonia changed a few things during the Seed Chamber scene.  the instrumental of the opening begins to play and plays throughout the first boss battle.
 * In Super Castlevania IV, Simon's Theme starts playing once you get Dracula's health below half.
 * In Baten Kaitos Origins, during the boss battle with, the amazingly creepy song 'Into the Spiral Tention' plays over the fight, instead of the regular boss music. Fitting, considering this is a massive Wham! Episode.
 * Earlier, during the segment where Sagi and Guillo escape Mintaka, the normal battle music doesn't play over the first few scripted fights.
 * Tales of Phantasia has the regular battle theme replaced with "Open Fire" during The War Sequence in Valhalla Plains and replaced with "Threatening Sky" during the Pegasus sequence following shortly thereafter.
 * The climax of Professor Layton and the Last Specter has, in lieu of the normal puzzle theme, "Theme of the Last Battle" play while you're puzzling the antagonist into submission as well as during the intermittent cutscenes.
 * The Legend of Zelda: Majora's Mask: If Link gets to the point where there are only six in-game hours left until the moon falls, the theme of the final hours will play in the background until the moon falls or Link goes back to the first day. The theme overrides any and all songs in the game other than dungeon music.
 * In Resident Evil 3: Nemesis, when the Big Bad Nemesis is stalking you, the BGM is overridden by "Feel the Tense". If playing with a scratched disc, it may be replaced by dead silence, making it even scarier.
 * If for some reason you decide to exit a boss's lair in Adventures of Rad Gravity, the boss music continues to play. Conversely, the Final Dungeon uses the boss music for its main theme, but switches to the regular action music when you fight Agathos.
 * In Super Contra (arcade), the miniboss of the final stage has its own unique BGM and victory fanfare, but when the Final Boss appears, it plays the original stage music again! This may have been a programming error.
 * In Twisted Metal: Black a more frantic music theme (different for each stage) takes over when there's only one opponent left.
 * In Legend of Legaia, when you are traversing a Mist Generator dungeon, the dungeon theme continues to play during random battles. This happens again for a certain sequence in Ratayu, and then again.
 * In Pokémon Ruby and Sapphire, when either the sun has intensified or there is a massive downpour, all overworld music (Including surfing and cycling) will be replaced with one ominous track.
 * In Pokémon Black and White, the dynamic music in Village Bridge will also override the surfing and cycling music.
 * Kinnikuman: Muscle Fight
 * Kinnikuman can override the BGM by using his Gyudon Ondo super and replace it with Kinnikuman Sensation.
 * Ramenman can override the BGM to one of his leitmotifs by using his level 3 version of the Camel Clutch
 * Black Hole can override the BGM to Bermuda Mystery by using his Black Hole Absorption desperation super.
 * Buffaloman and Terryman can override the BGM if their super meters are full. Terryman's theme is Texas Bronco and Buffaloman's theme is Devilish Buffalo.
 * Puripuriman can replace the BGM with "Burning Kinnikuman" with his Burning Puripuriman super.

Web Comics

 * A rare non-video game example comes from Homestuck's AlterniaBound, the Final Boss, Black King's theme song, Rex Duodecim Angelus. At one point, about five minutes in, the instrumentals are replaced by . It lasts for only a few seconds, but is unmissable, and is consistent with  one attack during the fight dealing more damage than anything else the trolls throw at him.
 * Used primarily because at that point, Gamzee had no Leitmotif. He got one shortly thereafter in "Blackest Heart".