Last Episode Theme Reprise

Since it's standard practice to make an Anime Theme Song as awesome as possible, said theme likes to find its way into a privileged position in the final battle. At The Climax of the series, when things are at their most epic, the theme gets played over the show itself. Typically we'll get to hear the verses not played in the opening, and sometimes the whole song is strung together for once.

The opening or closing theme can be used. Often this serves as an ultimate Theme Music Power-Up. Often it serves in this capacity for the show itself. The creators seem to be claiming their own Crowning Moment of Awesome with this music.

This is also common in Video Games, the most common being a reprisal or orchestral version of the main theme over the final dungeon or ending sequences.

Sub-Trope of Title Theme Drop. Related to Theme Tune Cameo, where the theme is shown to exist in-universe.

Anime and Manga

 * The Twelve Kingdoms, with "Getsumei-fuuei".
 * Tengen Toppa Gurren Lagann, with "Sorairo Days" during the climax of the final battle.
 * Dialed Up to Eleven in The Lights in the Sky are Stars, where a new, more epic recording of "Sorairo Days" (appropriately subtitled "Tengen Toppa Edition" ) is used.
 * An inverted case happens earlier. The song "Happily Ever After" is used as Simon's Theme Music Power-Up in episodes 11 and 15, then becomes the closing theme tune in episode 16.
 * Technically it's only the fourth-last episode, but it still counts when the extended mix of Yuusha Oh Tanjou kicks in for the final battle against the Primevals over Jupiter in GaoGaiGar.
 * Lucky Star, "Motteke! Sailor Fuku", a Dancing Theme, is used as the BGM to the cheerleader routine in the final episode.
 * Magic Users Club
 * Although the theme song 'Rondo Revolution' didn't play during the last episode of Revolutionary Girl Utena, the song 'Rose and Release', sung to a similar tune, was. This trope was played straight with the movie, which could be considered a finale to the series in many ways.
 * The Melancholy of Haruhi Suzumiya
 * Happens in both season 1 and 2 of Shakugan no Shana
 * The first opening song for Full Moon wo Sagashite is used for exactly six episodes than abruptly dropped for the rest of the fifty-episode series. This comes off as jarring, considering Mitsuki's musical repertoire literally consists of about three songs and she knows how to sing this one. It's brought back for ridiculous heartwarming effect for the last several minutes of the final episode.
 * In Japanese, "Moonlight Denetsu" plays in the first-season finale of Sailor Moon. (However butchered the rest of that episode was, most fans prefer the dub song, "Carry On".
 * Sailor Moon does it again in the finale of the last season, using the "Sailor Stars" opening theme during the final battle against Galaxia.
 * Gundam Wing reprises its first opening song, "Just Communication", when
 * Zeta Gundam features a slower version of its opening tune at the end of its final episode.
 * Cross medium example in the fighting game Magical Girl Lyrical Nanoha A's Portable: The Battle of Aces, which uses the non-vocal, electric guitar version of the opening from the Magical Girl Lyrical Nanoha A's anime as one of two possible final boss music.
 * Space Battleship Yamato, a.k.a. Star Blazers, did this a bunch with its opening theme being reprised as a slow violin-heavy instrumental towards the end of each season and in the movies.
 * Neon Genesis Evangelion's infamous "Congratulations!" scene in the last episode was accompanied by an instrumental version of its opening, "Cruel Angel's Thesis".
 * The final episode of Dragon Ball GT.
 * Slayers Evolution-R does this with the second season's theme song "Give a Reason" during the final battle of the fifth season.
 * Last Exile
 * Fullmetal Alchemist Brotherhood uses the second opening "Hologram" over the final episode's picture montage.
 * F-Zero Falcon Densetsu used the opening theme during the final climactic scene.
 * Aria uses the opening theme from its first season in the last episode of... the third season.
 * The second season finale of Minami-ke used the opening theme from the first season in the climactic Group Hug scene.
 * Inverted in two senses in Ga-Rei Zero, where "Paradise Lost" is put as the ending theme in the third episode, before being used as the official opening theme from episode 4 on.
 * Coyote Ragtime Show
 * The final episode of To Aru Kagaku no Railgun does with both the first and second opening themes.
 * The World God Only Knows uses the theme as background music for the last TWO episodes.
 * Not quite as repetitive as one might expect, as this is an 8-minute song which is varied to say the least.
 * SD Gundam Sangokuden Brave Battle Warriors: As Liu Bei becomes Celestial War God Dragon Liu Bei in the penultimate episode, the first ending theme, 'JUSTICE FIGHT; THE BRAVE LEGEND!' plays for great effect.
 * Busou Renkin's finale featured a reprise by the opening theme and the first ending theme.
 * Eureka Seven has the theme playing for the last-minute rescue on the last episode.
 * Yu-Gi-Oh! 5D's has the second verse of the current opening, "Road to Tomorrow ~Going my Way!!~" playing during Yusei's last turn of the final episode.
 * The English dub of Pokémon ended the first and thirteenth seasons this way. In both cases, the extended version of that season's theme was used.
 * The last episode of Cowboy Bebop features a variation of the closing theme, "The Real Folk Blues." The final two episodes are also called The Real Folk Blues, Parts I and II.
 * Inverted in Umi Monogatari, as the theme plays at the beginning of the last episode in a more somber tone as Marin and Kanon are near death.
 * Nurarihyon no Mago season 2 played the first opening theme of the season during the final attack of the last battle.
 * Macross Frontier has its original theme song "Triangler" reprise over the epilogue, which also serves as the ending credits, only this time sung by the two lead females. Being a song about a Love Triangle and Macross being a SHOW about a Love Triangle, this could be expected..
 * Witchblade switched its opening theme song for the last half of the series. The original opening theme song XTC comes back for the final episode, along with a new ending theme song by the same band.
 * Steins;Gate uses the opening theme for the videogame it was based on in the scene of Heroic Resolve when Okabe discovers how to save the world in the one-to-last episode.
 * In the last scene of the first season of Bakuman｡, the full version of the opening theme plays. Earlier in the episode, as the serialization meeting begins, the full version of the second ending plays.
 * In the last scenes of Mai-HiME, Shining Days plays. The extended ending has a Where Are They Now? Epilogue of sorts, with the full version playing over clips of the cast members.

Live Action TV

 * After nixing the very beloved theme tune "Overkill" in 2009, The Bill brought the theme tune back to close their last ever episode.
 * In a variation, the re-imagined Battlestar Galactica plays a version of the original series' theme during the eponymous ship's last scene on screen.
 * Happens in the final episode of Kamen Rider Double, symbolizing  Also happens in the penultimate episode (which is considered the final episode by some) where the ending song gets a Dark Reprise
 * In the final scene of Buffy the Vampire Slayer's final episode, a careful listener can hear a slower version of the main title song in the background music. Considering the events of that episode overturn all the premises of the entire series, it's eerily appropriate.
 * The original series finale for Scrubs (the last episode of season 8) ends on a banjo instrumental of the theme song. A behind-the-scenes reel of the cast and crew saying goodbye to one another over the credits is accompanied by an a capella cover of the theme song by the in-universe cover band The Worthless Peons.
 * Used in the finale of the first season of Dexter, played while Dexter gives a narration and everyone cheers
 * Stargate SG-1: Used at the end of the 8th season finale, which was believed to be the series finale before it was renewed. After SG-1, the Egyptian slaves wave their stolen weapons around and a glorious rendition of the Stargate theme plays in almost its entirety, signalling that the series had come full circle and returned to where the movie ended.
 * The main theme from Rome plays over the last scene of the finale, as Pullo and  melt into the city's bustling crowds.
 * The final episode of ER played the original theme song over the beginning and the end. It really stands out as the theme song had not been used in several years.
 * The final episode of Fraggle Rock ended with the Fraggles, the Doozers, the Gorgs, the Trash Heap, and Doc and Sprocket all singing the theme.

Video Games

 * Kingdom Hearts and Kingdom Hearts II's respective theme songs, "Hikari"/"Simple and Clean" and "Passion"/"Sanctuary", play upon the completion of each game.
 * And the final results screen of each game plays a reprise of "Dearly Beloved", the opening menu screen theme.
 * Wild Arms 4 has an extended version of its opening theme as last boss music.
 * Wild Arms 5 also uses the extended version of its opening theme as the music for the last boss. Wild Arms 2 was the first one in the Wild Arms series to use an opening as the theme for the final battle. In its case, it used a non-vocal rock version of the first opening.
 * Final Fantasy IV plays "The Red Wings", the song from the opening cutscenes, during the first half of its final dungeon. The last battle theme also includes a dark variation on the World Map theme, and the Where Are They Now epilogue expands on the Underworld theme.
 * Final Fantasy VI includes the opening theme in Dancing Mad, the final battle's theme.
 * Final Fantasy VIII opens with the chorus of "Fithos Lusec Vinosec." The last battle against Ultimecia's One-Winged Angel form begins with a distorted voice repeating this same chorus.
 * Done in both the Sonic Adventure games, as well as Shadow the Hedgehog and Sonic the Hedgehog 2006, which are Sonic Adventure games in spirit, and Sonic Colors, which isn't.
 * All three Super Smash Bros games does this, most notably is the end of the Subspace Emissary, with the translated lyrics.
 * Persona 3 does this twice. The true Final Battle is set against an orchestral version (with percussion and electric guitar) of the Persona series-wide theme "Aria of the Soul" (aka "The Poem For Everyone's Souls.") Then the final Final Battle (a scripted event) provides a heroic reprise of "Burn My Dread," opening theme and Leitmotif of Persona 3.
 * Persona 4 has "The Genesis", which eventually plays a reprise of the boss theme "I'll Face Myself" and finishes with an orchestral remix of the game's main theme "Reach Out To The Truth".
 * Fire Emblem: Path of Radiance does this in the most epic way. After you win, you hear an orchestral version of the fire emblem theme, which had previously only been heard in pixelated-game-boy-form
 * Star Fox Assault does this during its final boss fight with the theme heard when you turn on the game. It comes in triumphantly 43 seconds into the song. Bonus points if you can manage to
 * Mega Man Star Force 3 also does this in the final story boss, Not only this, but it's also an example of a Theme Tune Cameo, because Sonia has written the song.
 * Metroid Zero Mission. Once you get back your suit in Chozodia, the Brinstar Depths theme (first area) plays instead of the tense stealth music.
 * Fate/stay night: An instrumental of the opening theme "This Illusion" plays in the epic final showdown between

Web Original

 * The entirety of the oft loathed theme tune for Zero Punctuation appearing at the end of the hundredth installment. For some it Rescued it From The Scrappy Heap.
 * Ostensibly due to plagiarism, the Theme to Metal Gear Solid (and Metal Gear Solid 2 Sons of Liberty) was not present at the start of Metal Gear Solid 3 Snake Eater. However, it comes back gloriously orchestrated for the Twist Ending, right at the most powerful part.

Western Animation

 * Done in Megas XLR, where during the final battle, with dozens of robots on both sides, they all fight to an extended, instrumental version of Chicks Dig Giant Robots. It is pure, concentrated awesome.
 * Transformers Cybertron does this. As the Autobots taking part in the revived Space Bridge Project lift off in the four ancient starships, with Optimus Prime in command, the show's theme music - the first remix of the original theme to use the "Autobots wage their battles to destroy the evil forces of the Decepticons" line since the old cartoon- kicks in. The theme has to be looped because it's only thirty seconds, but it is so awesome. It wraps up with Optimus saying "Courage, teamwork, and hope for the future. Our adventure will continue as long as we remember the words of Primus: 'Til all are one." And then all the Autobots shout aloud "Transform!" The theme then plays one last time, straight-up during the Final Credits montage, which ends with a picture of Coby and Lori's wedding where Optimus is standing behind the newlyweds.
 * The original anime version did it too, with a version of one of its theme songs playing. The american version had to loop the song to fill the same amount of time.
 * In the first, and, as far as the creators knew at the time, last Futurama movie, a slightly remixed version of the theme is played during the climactic battle- and the Earth fleet is coordinated with it.