* BadExportForYou: The NES ''Life Force'' only allows two options per ship (instead of three like its FC counterpart) and lacks the multiple endings from the FC ''Salamander''; its sole ending is a static shot of the Konami logo while the ending theme plays.
* CowboyBeBopAtHisComputer: The story on the Game Boy box and manual of ''Nemesis'' claims you are the chief of the Interplanetary Police, piloting the Proteus 911 hunting King Nemesis down. Nowhere in the game is there a King Nemesis, and anyone who played Gradius before knows it's the Vic Viper you play as.
* DummiedOut: The Salamander arcade has several very good unused music tracks, some of which ended up being used in the Japanese Lifeforce arcade, while others did not.
* FollowTheLeader: A great many shooters followed the ''Gradius'' powerup system, sometimes expanding it into a between-levels "shop" where points could be exchanged for powerups, other times using it verbatim. Other shooters sometimes have the [[AttackDrone trailing Options]] that the series' fighters use.
* FranchiseKiller: The mediocre reception of ''Gradius [=ReBirth=]'' combined with the failure of its spin-off series ''VideoGame/{{Otomedius}}'' caused the death of the ''Gradius'' franchise as a whole. Outside of ''Gradius the Slot'' in 2011 and countless re-releases of older titles, no new games were ever released since then.
* HeAlsoDid: The ''Salamander 2'' soundtrack was mainly composed by Naoki Maeda, known by many for producing tracks for the ''VideoGame/DanceDanceRevolution'' series and serving as sound producer for a good chunk of it.
* KeepCirculatingTheTapes:
** The mainline games are fairly good about this, each game from ''I'' through ''IV'' having had about 1-3 {{Arcade Perfect Port}}s, but the ''Solar Assault Gradius'' sub-series never saw a console release (you may be lucky to find one at Chuck-e-Cheese's).
** ''[=ReBirth=]'' can no longer be purchased as of March 2018, due to the Platform/{{Wii}} Shop Channel no longer allowing purchases. By 2019, you won't be able to redownload it if you already have it. The only way to obtain it now without breaking the law is to get your hands on a used Wii that has this game.
* LateExportForYou:
** ''Gradius II'' was released in 1988 in Japan and Europe, but did not see an official release in North America until its inclusion in ''Gradius Collection'' in 2006, eighteen years later.
** ''Gradius Gaiden'' was released in 1998 in Japan, and took eight years to be released elsewhere. Like ''Gradius II'', its export took form of being one of the games on ''Collection''.
* MarthDebutedInSmashBros:
** Venom made his North American debut in ''V'' in 2005, 18 years after he debuted in the Japan- and Europe-exclusive ''Nemesis 2'' in 1987. Just to add insult to injury, his massive-brain form in this game looks nothing like how he does in the Platform/{{MSX}} games or in ''[=ReBirth=]'' where he's a comparatively normal green humanoid alien.
** James Burton, having also debuted in ''Nemesis 2'' in Japan and Europe, did not appear in any game released for the North American market until ''Gradius [=ReBirth=]'' in 2009, 22 years later.
** Gofer of ''Gradius II'' (1988) had to wait 10 years to appear in a game released in North America, namely ''Gradius IV''.
* MissingEpisode: Salamander's second and fifth levels - both of which are set in space and involve dodging asteroids - do not appear in the FC port/NES Life Force at all. Instead, stage 4 (volcano) has been moved to stage 2 while stages 4 and 5 are now something completely new (a vertical cell level, and a temple level, respectively)
* NoDubForYou: In some games like ''Salamander'' and ''V'', the voices are exclusively in English. Even worse in ''V'', the voices are subbed in Japanese version instead of dubbed.
* NoExportForYou: A few games remain Japan-only. ''Gradius II'' ([[Platform/NintendoEntertainmentSystem Famicom]])[[note]]although ''Gradius II'' is available in some form in all three major gaming markets, the Famicom port deviates in stage design pretty strongly[[/note]] and ''Salamander 2'' are two such examples.
** Subverted for games that never got released in North America, but did in ''Europe'', even though North America often gets priority over Europe with exports. The Platform/{{MSX}}-exclusive games (''Salamander'', ''Gradius 2'' / ''Nemesis II'', ''Gofer no Yabou Episode II'' / ''Nemesis III'') come to mind, as the system they're on was a flop in North America anyway.
** Salamander Portable for the Platform/{{PSP}} was never released outside of Japan. This is especially annoying since it perfectly compliments the Gradius Collection (which was released worldwide), containing all the games that were left out of the earlier collection (including the Platform/{{MSX}} Gradius 2).
** The original ''Gradius II'', released in 1988, remained out of the reach of the North American market until 2006 (as part of ''[[CompilationRerelease Gradius Collection]]'')--that is, for ''eighteen years''. Its [[Platform/TurboGrafx16 PC Engine]] port followed suit in 2009 with a Platform/VirtualConsole rerelease.
** A major reason why the Famicom port of ''Gradius II'' didn't make it outside of Japan is that it used of one of Konami's own VRC mappers, and Nintendo's policy of forbidding most if not all 3rd party mappers meant that it would have necessitated converting the code to one of Nintendo's MMC chips, a task they must have decided was too costly and difficult, especially given that the [=MMC3=], perhaps the only chip to be up to the task of handling [=VRC4=]'s bank switching to any degree, was too new and only used in one game to that point[[note]]Super Mario Bros. 2[[/note]].
** While ''Gaiden'' eventually got an export in the form of ''Gradius Collection'', it was included in the Japanese PS Classic and not any other region's version of the pseudo-console. Thus, ''Gaiden'' officially remains a PSP exclusive in Western regions, which also means that the 2-player feature is not available in those regions since ''Collection'' removes all multiplayer elements from each game.
* NoPortForYou: ''[=ReBirth=]'' is a [=WiiWare=]-exclusive, which is a very big problem because [[KeepCirculatingTheTapes Wii Shop Channel games can no longer be purchased as of March 2018 or downloaded effective January 2019]].
* PortOverdosed: The first two ''Gradius'' arcade games and the original ''Salamander'' got ported to plenty of platforms in some form or another. Particularly in Japan, where the series got the Deluxe Packs on the PS and Saturn, as well as Collection series on Platform/{{PSP}}.
* ReferencedBy:
** Vic Viper's models and related ''Gradius'' entities have appeared as ''TabletopGame/YuGiOh'' cards over the years. They even have the unique distinction among Konami franchises appearing in the card game for getting an entire archetype based on it: "B.E.S.", a series of cards based on the Bacterian alien fleet from the ''Gradius'' games. ''VideoGame/YuGiOhMasterDuel'' also includes a ''Gradius'' EasterEgg by way of the KonamiCode.
** KONAMI animation features both the KonamiCode and the 1P Start sound effect from the original ''Gradius'' for its animated logo.
* RefittedForSequel: The ''Gradius II'' track "Synthetic Life" was at first planned for the MSX ''Nemesis 2'', as part of a scrapped version of the fourth stage, which had an Egyptian temple theme with sphinx and pyramid enemies attacking the player. After the song and level were cut from the final ''Nemesis 2'', the track was repurposed for ''Gradius II'''s second stage, and an Egyptian temple themed level was eventually included in the NES port of ''Salamander''/''Life Force'', though as an entirely different level.
* SequelFirst: ''Gradius II'' was released in 1988 in Japan and Europe, but ''not in North America'', where it was officially unreleased until its appearance on ''Gradius Collection'' in 2006. ''Gaiden'' is a milder example; ''IV'' and ''Galaxies'' came after it and were released here before ''Collection'' (which included ''Gaiden'' as well).
* WhatCouldHaveBeen:
** [[https://shmuplations.com/gpg-gradius According to designer Kengo Nakamura]], the original ''Gradius'' was meant to have several different power-ups at the end of the bar, which is why it was labeled with a question mark. However, the final product only has a shield there, leaving its name an [[TheArtifact artifact]].
** Besides the cut Egyptian temple stage and the song “Synthetic Life” (re-used in ''Gradius II''), as mentioned in RefittedForSequel above, the MSX ''Nemesis 2'' also had a cut crystal-themed stage as its sixth level, with a unique boss to go along with it. This and the temple stage can be seen in a prototype build.
** The canceled racing game ''Vic Viper'' was meant to be Konami's answer to ''VideoGame/FZero'' series.
** ''Gradius V'':
*** An arcade version was in development, but was cancelled due to time constraints.
*** ''V'' additionally would have had a feature where selecting the same slot on the powerup gauge multiple times will swap that weapon out with another one of the same category (e.g. replacing Missile with Spread Bomb or Laser with Ripple, something similar to those in MSX ''Gradius'' games), but this was scrapped in favor of the traditional gauge select and unlockable gauge edit.
** The ''Salamander HD Remaster'', a remake of NES ''Life Force''/Famicom ''Salamander'', was slated for the release on mobile phones In similar fashion to ''Contra Evolution'', but was ultimately cancelled due to the closure of its developer, Konami Shanghai (a Konami subsidiary based in Shanghai). One of the staff members finished up the game and provided free download links however.
* WorkingTitle: The first game was named ''Scramble 2'' during development, as it was originally meant to be a direct sequel to ''VideoGame/{{Scramble}}''. According to [[https://shmuplations.com/gpg-gradius this interview]], it was only changed to ''Gradius'' after the core gameplay was nearly finalized, motivated by the need to make the game's instruction sheet.