The background music of the first level in many video games frequently becomes the theme associated with the series. Sometimes, the "first level" theme becomes so representative of the series that it supplants the planned Main Theme in later games and advertising material. After all, chances are that people will spend more time on the first level learning the ropes rather than admiring the title screen. Since most developers are aware of this, they'll be likely to spend a little more time on the Level 1 music, and perhaps put it in a higher number of levels due to the extra work put into it, further feeding into this trope. This trope is more common in linear games (like platformers and shoot-em-ups) as opposed to Sandboxes or [=RPGs=], where level 1 is often either [[QuickSandBox not clearly defined]] or played after spending an appreciable amount of time on the TraversibleWorldMap.

A Sub-Trope of BootstrappedTheme. If sequels continue to use the level 1 music from the first game, it's also a form of FirstInstallmentWins.
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!!Straight Examples of this trope include:

* ''Franchise/SuperMarioBros'':
** [[http://www.youtube.com/watch?v=wGX4obVl64w "Ground Theme"]], also known as the Overworld theme.
** Averted in ''VideoGame/SuperMarioBros2''. The [[http://youtu.be/fqtKBlK3YII title theme]] was an arrangement of the [[http://youtu.be/TBx-8jqiGfA underwater theme]] from the original.
** Likewise, when ''VideoGame/SuperMarioAllStars'' gave each game their own title themes, they were all based on the underwater theme as well. In order, here are the ''All-Stars'' themes for the original ''[[http://youtu.be/ZBny76cJGgc Super Mario]]'', ''[[http://youtu.be/iE1U6iM1glA Lost Levels]]'' and ''[[http://youtu.be/Z9UmwpiCZZE 3]]''.
* ''Franchise/SonicTheHedgehog'': [[http://youtu.be/SF9ZLNxHaBY Green Hill Zone]]. The [[http://youtu.be/eQ9l1BsqvAo original title theme]] never appears these days unless as a throwback (such as the title screen in ''VideoGame/SonicGenerations'', itself a throwback to the whole series).
* ''VideoGame/{{Kirby}}'': [[http://youtu.be/OCH6nQYflwY Green Greens]]
* ''VideoGame/{{F-Zero}}'': [[http://youtu.be/a0WzWdSVFmE Mute City]].
* ''VideoGame/KidIcarus'': [[http://youtu.be/NC0Hr9CrFRc Underworld]]. It has the same intro as [[http://youtu.be/p08wyrAYMrs the title screen music]], but the two themes differ from there.
* ''Franchise/{{Castlevania}}'': [[http://youtu.be/0AZ5XZHIDh0 Vampire Killer]].
** Also [[http://www.youtube.com/watch?v=EjazC45Qkww Bloody Tears]], the overworld theme for the second game.
** Also [[http://www.youtube.com/watch?v=78706bv98S8 Beginning]], the Level 1 theme for the third game. These three tunes are featured more than any others across the series. For example, in ''VideoGame/CastlevaniaJudgment'', they're used as the respective themes of Simon Belmont, Carmilla, and Trevor Belmont.
* ''VideoGame/{{Contra}}'': [[http://youtu.be/Tifv7qh_hmY Battle in the Jungle]], which is remixed in ''Contra: Shattered Soldier'' and ''Contra 4''.
* ''VideoGame/DonkeyKongCountry'': [[http://youtu.be/Ep9N-jFCht4 "DK Island Swing"]], also known as "Jungle Level", "Jungle Groove", or by the name of its rearrangement for ''VideoGame/DonkeyKong64'', "Jungle Japes". Slightly unusual in that the music changes tone halfway through in the original game, due to it actually being a mashup of two different pieces, but only the first half is usually remembered.
* ''VideoGame/{{Metroid}}'': [[http://youtu.be/T-2sE0Napg0 Brinstar]]. They played with it in ''VideoGame/MetroidZeroMission''--in it, the item/save tunes are versions that sound far closer to the original game's, which has a different melodic focus than the versions that came from ''Super Metroid'' and on that gamers tend to be more familiar with. This is used to great effect when [[spoiler:Samus gets her power suit back after being shot down by the Space Pirates]], causing the modified later-game jingle to sound out, reorchestrated, in full force. [[https://www.youtube.com/watch?v=LhAQfpbsymU Theme of Super Metroid]] is also considered to be this by some as well.
* ''VideoGame/{{Doom}}'': [[http://youtu.be/BSsfjHCFosw At Doom's Gate]] for the first game, [[http://www.youtube.com/watch?v=qURei6svd90 Running from Evil]] for the second.
** From, ''Final Doom, TNT: Evilution'' has [[http://www.youtube.com/watch?v=wAi1q0LkTs4 Sadistic]], while its sister game ''The Plutonia Experiment'' has [[http://youtu.be/cBu0Iqlrunw The Imp's Song]].
* ''VideoGame/FinalFight'': [[http://youtu.be/AgJq48fcySk BGM 1]] was remixed as [[http://youtu.be/sy8VW_VXgOA Guy's theme]] in almost all of his fighting game appearances (starting with the original ''VideoGame/StreetFighterAlpha''), and also served as [[http://youtu.be/lqE-5y_q1dk Haggar's theme]] in ''VideoGame/MarvelVsCapcom3''. The Title theme would later reappear as the third protagonist, Cody's theme in Street Fighter 4.
* ''VideoGame/StarFox'': [[http://youtu.be/eclAC0JQJYk Corneria]].
* ''VideoGame/RType'': [[http://youtu.be/BaPU7Kej0oo R9, To the Front!]]
* ''VideoGame/GhostsNGoblins'': [[http://youtu.be/gA_e0QpVdLc Haunted Graveyard]], which was used as Arthur's theme for ''NamcoXCapcom'', ''VideoGame/MarvelVsCapcom3'' and ''VideoGame/ProjectXZone''. Also used as an alternate EasterEgg theme for [[BigBoosHaunt Shade Man's stage]] in ''VideoGame/{{Mega Man 7}}''.
* ''VideoGame/{{Raiden}}'': "Gallantry".
* ''VideoGame/{{Gradius}}'': "Challenger 1985", whose melody also appears in the intro to the Stage 2 music for ''Gradius V''.
* ''VideoGame/BlasterMaster'': [[http://youtu.be/y7L9KXVMSQs "Area 1 (Forest)"]]. Remixes of this appeared in the first levels of ''Blaster Master: Blasting Again'' and ''Blaster Master: Overdrive''.
* ''VideoGame/JourneyToSilius'': [[http://youtu.be/NjG2ZjPqzzE "Space Colony Ruins"]], which is better remembered than the [[http://youtu.be/jkWYvENgxwA title theme]] (although the former uses the same bassline as the latter in its refrain) and is reused for the [[BookEnds last stage]].
* The NES ''VideoGame/{{Batman|Sunsoft}}'' game's first stage theme is closely associated with the title and there are plenty of covers and remixes of the song, both because of its sheer coolness and because the NintendoHard nature of the game made it the most frequently heard tune for players.
* ''VideoGame/{{Valis}}'': [[https://www.youtube.com/watch?v=CPl24eXTZTA "Flash of Sword"]](Stage 1), although the series also has an official recurring title theme, [[https://www.youtube.com/watch?v=DM-D5TV0ND4 "Fantasm Soldier"]].
* ''VideoGame/MetalGear'': [[http://www.youtube.com/watch?v=xh8Odw3wQbE The Theme of Tara]], the main infiltration theme in the [=MSX2=] version, was later reused as [[http://youtu.be/2swZCYSRFt8 Metal Gear's theme]] in ''VisualNovel/{{Snatcher}}'', as well as the [[http://youtu.be/jW0BurBNB58 VR Training]] theme in ''VideoGame/MetalGearSolid'' and [[http://www.youtube.com/watch?v=RLRIn6NwbTI plays]] during Solid Snake's debut in the story mode of ''Super Smash Bros Brawl''.
* ''GanbareGoemon'': The [[http://www.youtube.com/watch?v=u5LxQvPVDmw Stage 1]] theme was remixed as the background music for [[http://www.youtube.com/watch?v=R45Wch50aYI Sundowner's Garden]] in ''VideoGame/MetalGearRisingRevengeance''.
* The opening section of ''VideoGame/DungeonSiege'' features music that seems to have been written with this idea in mind, as the name of that track is "Main Theme 1," and variations on the theme are used in places throughout the game, including during the FinalBattle and the credits. The FinalBattle theme was also carried over into the tutorial level for ''Dungeon Siege II''.
* ''DynamiteHeaddy'' uses a variation of the level 1 music as its title theme.
* While ''VideoGame/{{Ikaruga}}'' has a few songs to choose from, the level 1 music is especially infectious and the main part of it is used again near the end of the game. The only other recurring song is a tune that plays for three bosses, including the one in level 1.
* The Franchise/TalesSeries has several main battle themes for each game. However, most crossover games tend to feature the first battle themes of each game.
* ''RadRacer'': [[https://www.youtube.com/watch?v=UBu92QFScvA BGM 1]], AKA Sunset Coastline.
* The first stage music of ''VideoGame/SupraMayroBross'' returned for ''Supra Mayro Kratt'' as the stage select theme. Since then, it is considered the main theme of the series.
* [[https://www.youtube.com/watch?v=LdL3CjiVLEo Final Battle]], the theme of the titular fortress from ''VideoGame/LufiaAndTheFortressOfDoom''.
* The first stage's theme from the first ''VideoGame/RushingBeat'' game has appeared in all of the games. However, the theme plays in the last levels of the sequels instead of the first.
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!!Subversions, aversions, and inversions include:

* ''Franchise/TheLegendOfZelda'': [[http://youtu.be/vGBVW2Yt1X4 Hyrule Overworld]] isn't quite a straight example, because the Overworld theme is a remix of the [[https://www.youtube.com/watch?v=yjmeb7HCeyU Title Screen music]], which also sometimes appears in its original form (such as in the ending credits of ''VideoGame/TheLegendOfZeldaLinkToThePast'').
* The ''VideoGame/BionicCommando'' theme appears to be a straight example, being the zone 1 music from the {{NES}} game but in the original arcade game the music is used on the second level.
* In the original ''VideoGame/SuperSmashBros'' for the Nintendo 64, this trope was in effect for most of the stages (including the aforementioned Mario, DK, Zelda, etc.). However, Kirby's stage uses the "Gourmet Race" from ''VideoGame/KirbySuperStar'' instead.
* The ''VideoGame/MegaMan'' series is all over the place with this trope:
** ''VideoGame/MegaMan1'': Cut Man's theme is a straight example as it is usually the first level selected.
** Averted and subverted in ''VideoGame/MegaMan2'' where the title theme is used to represent Mega Man in ''VideoGame/MarvelVsCapcomClashOfTheSuperheroes'' and the other iconic theme is the first level... of the boss's fortress.
** The ''VideoGame/MegaManLegends'' subseries averts this by having The Flutter Vs. Gesellschaft theme from later in the game as the Iconic theme.
** The {{retraux}} [[http://youtu.be/TwbQi_G9cB0 advertisement]] for ''VideoGame/MegaMan10'' featured a cheesy jingle set to the tune of the opening stage of ''VideoGame/MegaManX'' of all things.
*** Most definitely [[JustifiedTrope justified]], since ''VideoGame/MegaMan10'' [[NotToBeConfusedWith could also be written as]] ''Mega Man X''.
** In ''VideoGame/ProjectXZone'', X's theme is that of ''VideoGame/{{Mega Man X4}}'s'' opening stage.
** Mega Man's inclusion in ''VideoGame/SuperSmashBros'' uses a medley from ''VideoGame/MegaMan2'' for his theme.
* ''VideoGame/DoubleDragon'': the title theme is played during [[ThemeMusicPowerUp the final boss battle]], but during the bonus sibling match that occurs when two players complete the game together, the music changes to the Mission 1 theme. This also holds true to the NES version, which has Machine Gun Willy as the [[DemotedToDragon penultimate boss]] and Jimmy Lee [[AdaptationalVillainy as the final boss]].
** The arcade version of ''Double Dragon II'' uses a BossRemix of the title theme in its penultimate battle (again with Willy), prior to the final battle with the [[MirrorBoss Lee clones]]. In the NES version, where Willy is absent, this remix plays during the tractor battle in Mission 6.
** ''Super Double Dragon'' has a different title theme and the classic Double Dragon Theme is instead used as background music for Mission 5. The Japanese version ([[MarketBasedTitle titled]] ''Return of Double Dragon'') restores the Double Dragon theme to its rightful place and uses an arranged version of the Mission 1 theme from the original arcade game for Mission 5.
* In ''VideoGame/DynastyWarriors 2'', the theme for the Battle of Hulao Gate, "[[http://www.youtube.com/watch?v=7k_kgBN3bA8 Jump Into the Battlefield]]", is extremely popular and well known, even though the Battle of Hulao Gate is the second stage in the game after the Yellow Turban Rebellion.
* ''{{VideoGame/MOTHER|1}}'': [[http://youtu.be/QYqDCPg7GPE "Pollyanna"]] is the overworld tune that plays at the start of the game when Ninten is the only party member. It is not considered the theme song for the game (that is usually either [[http://youtu.be/f5_R4WMBZjg the title screen theme]] or [[http://youtu.be/85XM_Nl7_oo Eight Melodies]]), but it is considered the theme for ''the {{VideoGame/MOTHER}} series as a whole''.
* NiGHTS plays with this trope. While the main character's theme, Dream Dreams, is considered the series' main theme, the first level's song, Paternal Horn, is treated as a secondary theme and is used in every SegaSuperstars game that features a [=NiGHTS=] level.
* ''AnarchyReigns'' has many {{Leitmotif}}s for its characters, but the theme that caught on most is Tre-Dot's ''[[http://www.youtube.com/watch?v=iqPT26AH940 Ruthless]]'', which was used as the first song in-game from the demo.
* Reversed in VideoGame/MegaManZero where the first level's theme was Zero's theme from the original X game.
** And on the topic of Zero ''VideoGame/MarvelVsCapcom3'' averts this by using the Copy Zero battle theme from X2.
* The Stage 1 music in ''Shockman is'' the title theme.
* Typically played straight in Namco Arcade games but there are exceptions.
** Pac-Man lacked any level music in the orginal game. However, the [[https://www.youtube.com/watch?v=FJd6TMOZuJQ Intermission music]] is often used instead. [[https://www.youtube.com/watch?v=8d6mvLswDkU A remix]] is the theme for Pac-Man's room in Namco Museum Vol 1, and it's also remixed into the theme of the second set of levels from Pac-Mania, [[https://www.youtube.com/watch?v=_sir7iTg_CU Pac-Man's Park]], which in turn is used as a recurring theme in other games and as ThemeMusicPowerUp in PacManAndTheGhostlyAdventures. However, the music from the first set of levels, [[https://www.youtube.com/watch?v=Wlg9weUmP9w Block Town]], is used [[https://www.youtube.com/watch?v=MaJIqf0b56c as part of a medley]] with the Pac-Man Park theme in Super Smash Bros 4.
** WonderMomo's theme isn't the level music but rather the [[ThemeMusicPowerUp theme]] that plays when in Wonder mode.
* [[https://www.youtube.com/watch?v=AMqTOz5lHoQ&index=2&list=PLF0FAD6732B277862 Bombing Mission]] from ''FinalFantasyVII'' continue from the opening cutscene to the first few screens, with a musical transition between the two. The whole thing is iconic to the game.
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