* CashCowFranchise: The entire series is Compile heart's flagship title.
* DevelopmentGag: In ''[=ReBirth=];1'', when Neptune, joking obviously, says "Iffy" must mean "I Feel For You" (as in IF loves her), Compa says they should call her "Ai", as that's Japanese for love. IF's Japanese name is "Aiefu" and she's called "Ai-chan" in the Japanese version. (The original Japanese dialogue for this scene had Compa call her "Love-chan" instead).
** A running gag in the game is that most people have inexplicable difficulty pronouncing Neptune's name. On one occasion, it's accidentally rendered "Neptunia." This is a Development Gag rather than a form of TitleDrop because it's also the case in the original Japanese voice track, where Neptunia isn't part of the title -- the last word of the Japanese title for the series is simply "Neptune", after the protagonist, but it was changed to "Neptunia" for overseas release, which this references.
* MarthDebutedInSmashBros:
** As ''VisualNovel/SteinsGate'' wasn't released in North America until after this game, [[spoiler: Kurisu Makise, Mayuri Shiina, and Itaru Hashida]] ALL made their North American debut in this game as 5pb's Skills.
** The crossover with [[Characters/SegaHardGirls Sega Hard Girls]] will be their first appearance on US consoles, as [[Anime/HisCooolSeHaGirls home series]] and merchandise was not released, marking their first English dubbed appearance by proxy.
* NamesTheSame: This Black Heart is definitely not [[Comicbook/GhostRider the son]] [[VideoGame/MarvelVsCapcom2 of Mephisto]] nor a boss from ''VideoGame/BattleGaregga''.
** Also Noire and Vert are not working as a QuirkyMinibossSquad [[Anime/DogDays for a lion princess]].
* NoBudget: The first game ran out of money and was mostly unfinished. The second and third games were given a higher budget and received a warmer reception.
* NoExportForYou: Sadly, Australia hasn't gotten any games past the first one. If an Australian wants ''mk2'' or ''Victory'', they'd have to import it.
** ''Victory'' eventually got a very small print run down under, and all three games can be purchased from PSN.
* OneOfUs: Katsuhiro Harada, the video game producer of the ''VideoGame/{{Tekken}}'' series likes Noire. And pretty much one of the main reasons why we even get Tekken in ''VideoGame/HyperdimensionNeptuniaV'' (they couldn't get the Namco name so they had to settle for this).
** And Creator/RieTanaka as well. When you can get the platinum trophies of all three games ''[[https://twitter.com/AndyTaichou/status/319266220660621312/photo/1 in the English Version]]'', you're definitely one.
* RecursiveAdaptation: In [[Anime/HyperdimensionNeptuniaTheAnimation the anime]], this pops up when Vert ends up playing ''Four Goddesses Online'', an MMO. A pause screen shows that she's actually playing ''[[VideoGame/HyperdimensionNeptuniaVictory Victory]]''.
* RelationshipVoiceActor:
** [[Creator/StephanieSheh Financier]] as [[Creator/WendeeLee White Heart's]] assistant in the first game.
** The English dub of ''mk2'' has at least 6 [=VAs=] who have worked on ''Manga/ShinryakuIkaMusume'' and ''seven'' who have worked on ''Anime/PuellaMagiMadokaMagica'' and ''Anime/KOn''.
** [[Creator/KiraBuckland MarvelousAQL]], [[Creator/CristinaValenzuela Compa]], [[Creator/XantheHuynh Falcom]], [[Creator/CaitlinGlass 5pb.]], [[Creator/EricaLindbeck Uzume]], [[Creator/LauraPost Arfoire]], [[Creator/ChristineMarieCabanos Nepgear]] and [[Creator/CassandraLee Gust]] are [[Franchise/LoveLive Umi Sonoda, Kotori Minami, Hanayo Koizumi, Maki Nishikino, Eli Ayase, Nozomi Tojo, Yukiho Kosaka and Kira Tsubasa]].
** Creator/AsamiImai (Noire) and Creator/EriKitamura (Uni) do not only star a lot together, they are also a seiyuu unit: ARTERY VEIN.
** The same goes to Creator/YuiOgura (Rom) and Creator/KaoriIshihara (Ram); they are the unit [=YuiKaori=] and even share the same color themes with the twins, only reversed.
** An odd private life example: Creator/MikaKanai (Histoire) is the ex-wife of Creator/RieTanaka's (Neptune) husband, Creator/KoichiYamadera.
** Four members of the unit Aice⁵ are in this franchise: [[Creator/YuiHorie Nepgear]], [[Creator/ChiakiTakahashi Magiquone]], [[Creator/AkemiKanda Falcom]] and [[Creator/MasumiAsano CyberConnect2]].
* TheOtherDarrin: 5pb., voiced by Creator/MelaLee in the first game, is voiced by Creator/JulieAnnTaylor in the second.
** Same goes for the anime's English dub. Creator/TiaBallard took over Creator/SandyFox as Peashy, Megan Shipman took over Creator/KateHiggins as IF, Creator/CaitlinGlass took over Creator/MelaLee and Creator/JulieAnnTaylor as 5pb, and Morgan Garett took over Creator/JulieAnnTaylor as Rei Ryghts.
** in the English dub of ''VII'', Vert's voice actress, Creator/TaraPlatt, had to be replaced by Creator/CarrieKeranen, who also voices Rom.
* TrollingCreator: In [[Anime/HyperdimensionNeptuniaTheAnimation the anime]], [[spoiler:episode 13 begins with Neptune readying to [[VideoGame/HyperdimensionNeptuniaMk2 be exterminated by Nepgear]] [[EarnYourBadEnding with a sword that can kill Goddesses.]] [[DoesThisRemindYouOfAnything It's frustrating at first]], [[MoodWhiplash until you saw Neptune]] [[ItMakesSenseInContext turned into a lot of Dogoos!]]]]
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