Click [[DarthWiki/{{Ikaruga}} here]] to switch polarity.
->''"I will not die until I achieve something.\\
Even though the ideal is high, I never give in.\\
Therefore, I never die with regrets."''
-->-- Proverb that appears on every startup of the game

''Ikaruga'' is a modernized take on the "BulletHell" school of [[ShootEmUp Shoot 'em Ups]], developed by Creator/{{Treasure}}. It's widely regarded as one of the best examples of the genre, and a SpiritualSuccessor to ''VideoGame/RadiantSilvergun''.

Here, everything comes in one of two polarities: black or white. Black ships fire black shots, and white ships fire white. Your ship is unique in that you can switch between the two polarities at will. Your ship's BattleAura can [[EnergyAbsorption absorb bullets]] of the same polarity, but is [[OneHitPointWonder destroyed by shots]] of the opposite polarity. However, ''your'' shots do damage to both polarities, with double damage to targets of the opposite polarity, giving you the option to fly with your defences down to increase your offensive power. Absorbed bullets [[ChargedAttack charge up]] your special attack, a [[{{Roboteching}} homing]] BeamSpam. Finally, the scoring system allows you to accumulate "chain" multipliers by destroying three enemies of the same polarity in a row.

That's all there is to the game: no other gimmicks, no other features. Just five levels of careful design, switching polarity, and more bullets than you can shake a stick at. ''Ikaruga'' is a work of art that way: it takes a simple idea and plays that idea to its most logical extreme. All five levels are ThatOneLevel in one way or another, but there is something to be said for elegance.

Released as an arcade game (using the Sega NAOMI platform) and on the [[UsefulNotes/SegaDreamcast Dreamcast]] in Japan in 2001, it was later ported to the [[UsefulNotes/NintendoGameCube GameCube]] around the world in 2003. In 2008, it was ported to UsefulNotes/{{Xbox 360}} via UsefulNotes/XboxLiveArcade. In 2013, a port of the game was released for {{Android|Games}} smartphones. A Windows PC port based on the Xbox 360 version of ''Ikaruga'' was [[http://steamcommunity.com/sharedfiles/filedetails/?id=183195387 greenlit]] for UsefulNotes/{{Steam}}, and consequently released on February 18, 2014.

!!WARNING: The big list is approaching at full throttle. According to the data, it is identified as Tropes. NO REFUGE
* TwoAndAHalfD: Almost everything in the game is 3D, but the game, being a BulletHell shooter, plays out on a 2D plane with some cutscenes shown on a full 3D plane at the start of each stage and boss, as well as at the end of the entire game.
* ActionGirl: Kagari, pilot of the Ginkei.
* AdvancingBossOfDoom: Chapter 3's BossInMookClothing near the end.
* AllThereInTheManual: In the true tradition of shoot 'em ups, the only place you will find anything remotely resembling a coherent plot for the game. And not even in that for the [=GameCube=] version.
** [[http://www.gamefaqs.com/console/dreamcast/file/561887/23884 CTRL+F 'Extras' to read an English translation of the prologue from the Dreamcast GD-ROM]].
* AnimalMotifs: Ikaruga and Ginkei, the two ships, are named after birds. Ikaruga is also the name of the village where it was built.
* ArcWords: ''Ikaruga departs.''
** ''I will not die until I achieve something''
* ArtifactOfDoom: The PostFinalBoss
* TheAtoner: Kagari, as she used to be a mercenary for the Horai.
* BattleshipRaid: The whole of stage four.
* BigBad: Horai Tenro
* BiggerOnTheInside: The arcade version of the game takes up only ''eighteen megabytes''. Trust us, that's impressive.
** The [[http://marketplace.xbox.com/en-US/Product/Ikaruga/66acd000-77fe-1000-9115-d80258410878 XBLA version]] is no slouch either; for a game enhanced for 720p, it squeezes by at fifty megabtyes, which is saying more than other shooters on the service enhanced for high-definition.
* BioAugmentation: This is Kagari's InformedAbility, which in-universe makes her more resistant to CombatBreakdown than a normal human like Shinra.
* BittersweetEnding: Shinra and Kagari [[DidYouJustPunchOutCthulhu destroy the Stone-Like]], breaking the cycle from ''VideoGame/RadiantSilvergun'', but [[spoiler:[[TheHeroDies they die]] [[HeroicSacrifice in the process]]]].
* BossInMookClothing: Subverted in Chapter 5 with the huge ships that fire massive sprays of bullets...except the bullets are all in ''one color'', allowing you to safely rapidly soak up bullets for a counterattack.
* BossWarningSiren: In the same vein as ''Radiant Silvergun'': "'''WARNING:''' The big enemy is approaching at full throttle. According to the data, it is identified as 'Butsutekkai'. ''' NO REFUGE'''"
** Contrary to [[UrbanLegendOfZelda popular belief]], that message never changes; "Butsutekkai" is referring to something else and is not the name of a boss. Eboshidori (the chapter 1 boss) gets misnamed frequently.
* BottomlessMagazines: Averted in the console-exclusive Prototype Mode. Firing a shot uses one bullet, and firing your HomingLasers uses 120. [[EmergencyWeapon If you run out of bullets you'll be downgraded to a short-range attack.]] Bullets can be replenished by absorbing enemy bullets, and you can store up to 999 bullets.
* BulletHell: While its difficulty has arguably been eclipsed by some of the more recent entries in the genre, the game will still throw some truly intimidating patterns at you. [[http://ryuzie.sakura.ne.jp/ikaruga/text/tageri/tageri_big.jpg Perhaps the most infamous example...]]
** Though this game allows you to fly straight into enemy attacks so long as your color matches what's being shot at you. The real trick is knowing how to flow seamlessly between the polarities in times when both colors are staggeringly close to one another (you might be absorbing a black laser but as you are, tiny white globs are making their way towards your ship and you need to figure out how to either dodge them or safely switch polarities without getting yourself blown up by the black laser).
* CastFromHitPoints: Simply piloting the Ikaruga and Ginkei prematurely ages the pilots' brain cells.
* ChainReactionDestruction: Most of the bosses do this when killed, with parts of them breaking away and blowing up with smaller accompanying shockwaves just before their central part explodes violently.
* ChargedAttack: The "collect" kind. Notably, you can use the attack even if the meter isn't fully charged; you just get fewer homing lasers from your BeamSpam.
* ComputerVoice: The Ikaruga and Ginkei fighters. Their voice is somewhat hard to comprehend though especially during the epilogue.
* CoresAndTurretsBoss: Stage 4 boss and MiniBoss.
* DamnYouMuscleMemory: The Xbox 360 port slightly changes some of the enemy formations, which can trip up players who are used to previous ports.
* DangerousForbiddenTechnique: The Ikaruga's and Ginkei's final attack, which involves releasing all the ship's [[PowerLimiter restraining devices]] and has a very good chance of blowing it up.
* DarkerAndEdgier: Treasure somehow took the incredible bleakness of ''VideoGame/RadiantSilvergun'' and make it darker, in particular with the nearly monochrome watercolor artwork and dysfunctional heroes. However, [[spoiler:it has a LighterAndSofter ending.]]
* DeconReconSwitch: [[spoiler:''Ikaruga'' deconstructs the gameplay and story elements in bleak detail, and reconstructed later on at the same time as {{Minimalism}} kicks in, giving players [[BittersweetEnding an (unusually bittersweet) good ending]] they should deserve.]]
* {{Determinator}}: Shinra is stated in the backstory as someone who, despite being cool-headed, is also very adamant in his beliefs. This, combined with his goal of wanting to have absolutely no regrets when he dies, sometimes makes him look like a DeathSeeker in the eyes of others.
* TheEmpire: The Horai
* EternalRecurrence: Spelled out as such in the final chapter and then defied with the destruction of the PostFinalBoss.
--> '''[[FinalBoss Tageri]]''': It is impossible to cut off this [[TitleDrop metempsychosis]] forever. You can also see it, can't you?
* EvilAllAlong: The [[spoiler:Stone-Like]], in contrast to its BlueAndOrangeMorality nature in VideoGame/RadiantSilvergun, is shown to be downright evil here, being the driving factor that motivates the Horai to begin their conquest of the world in the first place.
* AGodAmI: Horai Tenro and her followers, once they found the [[ArtifactOfDoom Power of the Gods]] and started calling themselves the Divine Ones.
* GratuitousEnglish: A few Ikaruga-related art pieces can be seen with the phrase [[http://img61.imageshack.us/img61/8154/wall03jx2.jpg "I'm not regret."]]
* HeelFaceTurn / DefeatMeansFriendship: Shinra is attacked by Kagari in the prologue. After he defeats her ''and'' stops her from committing suicide, she decides to help him out instead.
* HitboxDissonance: Knowing the exact position of your hitbox is vital to getting the Dot Eater! rank. You have to be very precise in your positioning in order to get past walls, blocks, and enemies you're normally suppose to shoot to safely progress.
* HoldTheLine: Just like ''Radiant Silvergun'', [[spoiler:the PostFinalBoss disables your weapons]]. The only objective is to survive for 60 seconds.
* ImpressivePyrotechnics: Any time a boss is destroyed.
* KaizoTrap: When the boss of Stage 2 dies, the second plate-like object that protects its weak points gets blown off. If your ship is directly below it, you can still die from getting hit by it, [[http://www.youtube.com/watch?v=5RFxlMnxPkQ&t=08m56s like so]].
** If you defeat the final boss but [[spoiler:fail to survive the [[PostFinalBoss Stone-Like]], whose battle takes place ''after'' the final chapter]], you get NoEnding.
** Inverted with the [[spoiler: [[PostFinalBoss Stone-Like]], which is destroyed by the last volleys from your ships after your own self-destruct.]]
* LaResistance: Tenkaku, which was defeated before the game even starts.
* LighterAndSofter: {{Reconstruct|ion}}ed [[DeconReconSwitch in a way]]. The story is somewhat more positive in tone, and ends with [[spoiler:a BittersweetEnding rather than one where [[StableTimeLoop nothing]] [[ShootTheShaggyDog gets fixed]].]] The game is also [[SequelDifficultyDrop easier]].
* MeaningfulName: Ikaruga is the name of the Japanese Grosbeak (and a village where said birds are found). All the mooks, the bosses, and the Ginkei (Player 2 ship) are also named after a bird in Japanese. The Sword of Acala and [[spoiler:the Stone-Like]] are references to Vajrayana Buddism.
* MickeyMousing: The musical score is synchronized to the progression of the levels.
* {{Minimalism}}: In contrast to ''Radiant Silvergun''[='=]s complex weapon scheme and weapon levels, ''Ikaruga'' only gives you a basic rapid-fire blaster with constant firepower and a {{homing laser|s}} ChargedAttack.
* MilesToGoBeforeISleep: Kagari, although this is not apparent beyond the backstory. After meeting Shinra, as well as the villagers who gave him the Ikaruga and outfitted her Ginkei with the same ReversePolarity technology that exists on the Ikaruga, she found their idea of "freedom" to be something that could possibly surpass Horai's goal of conquest, and wants to see it for herself before she dies.
* MisbegottenMultiplayerMode: 2-player mode is overall a worse experience than 1-player. First, players don't overlap each other's ships, they will push one another, potentially into an object and killing each other. Second, ''Ikaruga''[='=]s scoring heavily emphasizes precision shooting, and chains are separated by player, meaning that both players will have a very difficult time trying to score well due to accidentally [[{{Griefer}} or otherwise]] shooting each other's targets.
* NintendoHard: Good ''Lord'', though this is somewhat mitigated by the fact that the console versions give out more credits as you log in more game time, and that even on the harder difficulties, it is relatively tame when compared to its predecessor, ''VideoGame/RadiantSilvergun''. Good luck unlocking most of the secret content though, which usually requires 1-credit clears of different game modes.
* NotActuallyCosmeticAward: Only if you're playing the Xbox 360 port and also have ''VideoGame/RadiantSilvergun'' on the same platform: Unlocking any achievement in ''Ikaruga'' unlocks its scoring system for use in ''RSG''.
* ObiWanMoment: From the [[spoiler:Ikaruga]] right after [[spoiler:its restraining device is turned off.]]
* OneHitPointWonder: The Ikaruga and Ginkei can absorb unlimited hits from shots of the same color as their current polarity. Take one hit from a shot of the opposite color, however, and...'''''[[StuffBlowingUp boum]]'''''.
* OneWordTitle
* PacifistRun: It is perfectly possible to complete ''Ikaruga'' without ever firing a single shot. Doing so for an entire level earns you the rank of "Dot Eater!"
* PowerLimiter: The Ikaruga and Ginkei have these to prevent their ships from blowing up from storing too much excess power. [[spoiler: Turning this off allows the pilot(s) to use the DangerousForbiddenTechnique and destroy the final boss in a HeroicSacrifice.]]
* RankInflation: Good luck getting those elusive "S++" rankings, buddy!
* RecurringRiff: Certain riffs are present in the majority of the songs.
* ReversePolarity: The main gameplay mechanic.
* {{Roboteching}}: Your homing lasers and some of the enemies projectiles will arch and bend to their targets.
* RuleOfSymbolism: The chapter titles—Ideal, Trial, Faith, Reality and Metempsychosis—represent Man's struggle towards enlightenment, with the aura-enveloped Ikaruga craft symbolising the human soul. Apparently.
* ScoringPoints: The game uses ''RSG''[='=]s chaining system, but with a few twists to make it more beginner friendly: After every three enemies you are allowed to change enemy color, and the chain bonus maxes out sooner at 25,600 points for your 9th chain and above, meaning screwing up once won't completely wreck your score. Additionally, since scoring is not tied to your ship's firepower, it is possible to complete the game in a reasonable timeframe without any regard to scoring.
* SeeminglyHopelessBossFight: After defeating Tageri, [[spoiler:the Stone-Like emerges from the remains]] and attacks you with several different patterns of bullets for 60 seconds. You can't even shoot, much less damage it. After you dodge and absorb the BulletHell, your ship [[spoiler:performs a HeroicSacrifice BeamSpam with the energy charged up during that time. Shinra [[AscendToAHigherPlaneOfExistence ascends to a higher plane of existence]] according to the storyline in the Japanese version.]]
* SequelDifficultyDrop: The game, as notorious as it is for difficulty, is still easier than ''Radiant Silvergun''. The game is shorter, your weapons do not require scoring well ([[PacifistRun or even at all]]) to maintain effectiveness throughout the game because ''they don't power up'', and even if you do play for score, you can now change enemy color after each chain, allowing you to play for score and still destroy most of the enemies.
* SpiritualSuccessor: To ''VideoGame/RadiantSilvergun''. Tageri's very definitely final form, and [[AllThereInTheManual what happened to those who came across it]], is extremely similar to what happened to the researchers in ''Silvergun''.
** SpiritualAntithesis: Simultaneously. Silvergun featured a large assort of weapons and power-ups, Ikaruga only has fewer simple weapons. Silvergun ''requires'' learning how to score in order to keep weapons powered up, but Ikaruga can be reliably completed without learning how to score and in fact recognizes {{Pacifist Run}}s. Silvergun has a bright, colorful environment and anime-esque cutscenes, Ikaruga's confined mostly to red/blacks and white/blues and uses much more realistic character designs. Silvergun's story starts comical but swiftly becomes an impossible struggle against an omnipotent godlike entity [[spoiler: which ends with everyone's death and the cycle beginning anew]], Ikaruga's story starts with the sole survivor of a failed resistance movement charging off to face an unstoppable army's entire force ''alone'' [[spoiler: and ''winning'', even managing to destroy the entity from ''Silvergun'' in a DyingMomentOfAwesome.]]
* TennisBoss: Battling Tageri can provide shades of this as both it and you trade homing lasers with each other. Even better, its health is scaled so that if you hit every return shot, [[MickeyMousing it'll die exactly at the end of the musical phrase]]. However, given that Tageri has 30-odd life bars, which are progressively depleted each time it takes a hit from your weapons fire, this trope is ultimately a subversion.
* ThemeNaming: The levels are named after the stages of enlightenment in Buddhism.
* TimeLimitBoss: Every boss battle, though you don't lose if time runs out... the boss simply moves on to other, more important things, leaving you free to go on. Apparently. Eboshidori will even FacePalm[[https://www.youtube.com/watch?v=Nh8UskS0Gl8&t=04m09s ]]!
* TitleDrop: In the weirdest sense. The birds that are flying in the credits? Japanese Grosbeaks. Ikaruga literally means "Japanese Grosbeak."
* TouchedByVorlons: The ruler of the Horai was a beautiful woman who came across [[spoiler:the Stone-Like during an excavation]]. She turns into a powerful, insane old hag bent on conquest.
* UnreadablyFastText: Seen (very briefly) at the start of each stage.
* YinYangBomb