History Film / OOODenOAllRidersLetsGoKamenRiders

** The film states it's set in 1971, but most of the elements shown in the past (the Kamen Rider Squad, the designs of the Double Riders outfits, the outfits of the Shocker grunts, Ikadevil and Ambassador Hell are shown as resurrected despite the fact that they didn't originally die until 1972) are more consistent with elements from 1972.

* FakeShemp: Inevitable, given the number of past heroes and villains going back to 1971. Aside from the main stars, almost all of the Kamen Riders appear in-costume only and voiced by replacement voice actors. It also affects many of the villains, along with the other four "allies of justice", though Creator/HiroshiMiyauchi returns to voice [[Series/KaiketsuZubat Zubat]] as well as [[Series/KamenRiderV3 V3]], and Creator/TomokazuSeki, who previously voiced Series/{{Kikaider}} in ''[[Series/AndroidKikaiderTheAnimation Android Kikaider: The Animation]]'', voices the tokusatsu incarnation of the character here. Really, it's surprising that so many ''were'' the original actors.

* MythologyGag: [[spoiler:Rock Great Leader is a beefed-up version of the Great Leader's Delza Army incarnation from the finale of ''Series/KamenRiderStronger''.]]

* ArcNumber: 40.

* DemotedToExtra: [[Series/KamenRiderDecade Decade]]'s appearance here has him as FakeShemp in a quick cameo like many of the past Riders.

* OneWingedAngel: [[spoiler:The Great Leader transforms into the Rock Great Leader after OOO defeats his normal form.]]

* PlotHole: A lot of plot elements are either pulled out of or disappear into nowhere, to the point where thinking about them too hard will probably make your head throb.

* WhatAboutTheMouse: At no point in the movie is the timeline actually fixed. Shocker is defeated in the present by the Riders (Most of whom shouldn't exist in this timeline anyway), but when the credits role, the bad timeline is still the one which exists.

** [[Series/KamenRiderV3 Turtle Bazooka]] is present despite the fact that Destron wasn't created until 1973, after the defeat of Gel-Shocker. One ''could'' write that off as Shocker simply creating the monster earlier in this timeline...if it wasn't for the fact that it still has the Destron symbol on its belt.

After Ankh accidentally coughs up a Cell Medal in the past while travelling with New Den-O, Shocker uses the technology to create a new Kaijin that manages to defeat [[Series/KamenRider the original Double Riders]]. Due to this, the past is rewritten so that Dai-Shocker now rules the world, and all the other Riders cease to exist. It's up to the Kamen Riders OOO, Den-O and New Den-O, accompanied by Ankh, to fix the mess they caused and save all of humanity.

* TheSlowPath: One of the two {{Tagalong Kid}}s [[spoiler:gets left behind in the past. He would grow up to become the Shocker scientist who removed the Double Riders' brainwashing, and, shockingly, his best friend's father.]]

* ArcNumber: 40

* DemotedToExtra: [[Series/KamenRiderDecade Decade]]'s appearance here has him as FakeShemp in a quick cameo like many of the past Riders. Also, there is no hint of Ryotaro and Hana, the main human characters of the original ''Den-O'' series.

* ForWantOfANail: The whole reason that the BadFuture exists is because [[spoiler: Ankh's greed in trying to get the Core Medals caused him to leave, causing Eiji to go after him and get into a scuffle. One of his Cell Medals dropped out during the scuffle and escalated to the main plot of the movie.]]

* TheWorfEffect: [[spoiler:The Shocker Greed is shown to be powerful enough to defeat the [[Series/KamenRider Double Riders]].]]
** [[spoiler:Gets on the receiving end later when they have their rematch.]]
* [[spoiler: YouAreNotAlone: All of the previous Kamen Riders arrive to assist their brethren in their hour of need.

* ChekhovsGunman: The ManInWhite who threw the OOO Driver back to Eiji.

* BadFuture: Ankh [[NiceJobBreakingItHero unwittingly causes a Butterfly Effect]] when he gets jostled hard enough to cough up a Cell Medal while in the past with New Den-O. This Cell Medal is picked up by a Shocker goon, who then takes it to General Black. As it turns out, they had been experimenting with a reverse-engineered Core Medal. The resulting Greeed ended up defeating the Double Riders, causing a future where Shocker and other such evil organizations control the world.

* [[spoiler: YouAreNotAlone: All of the previous Kamen Riders arrive to assist their brethren in their hour of need. [[CrowningMomentOfHeartwarming And it is glorious.]]]]
--> [[spoiler:[[CrowningMomentOfAwesome "It's not just four Kamen Riders!"]]]]

* CanonWelding: When [[Series/KamenRiderStronger General Shadow]] runs away, he is stopped by four other heroes. As Owner notes, "Kamen Riders aren't the only allies of justice." These four heroes are Series/{{Kikaider}}, Kikaider 01, {{Inazuman}}, and Series/KaiketsuZubat, all made by Creator/ShotaroIshinomori.

* BigDamnHeroes: During the battle in the present, [[spoiler:KamenRiderV3 arrives, leading the other main Kamen Riders. When the Great Leader transforms, Kamen Rider Birth arrives, leading the Secondary Riders.]]

* CanonWelding: When [[Series/KamenRiderStronger General Shadow]] runs away, he is stopped by four other heroes. As Owner notes, "Kamen Riders aren't the only allies of justice." These four heroes are Series/{{Kikaider}}, Kikaider 01, {{Inazuman}}, and Series/KaiketsuZubat, all made by ShotaroIshinomori.

* FakeShemp: Inevitable, given the number of past heroes and villains going back to 1971. Aside from the main stars, almost all of the Kamen Riders appear in-costume only and voiced by replacement voice actors. It also affects many of the villains, along with the other four "allies of justice", though Creator/HiroshiMiyauchi returns to voice [[Series/KaiketsuZubat Zubat]] as well as [[Series/KamenRiderV3 V3]], and Creator/TomokazuSeki, who previously voiced {{Kikaider}} in ''[[Series/AndroidKikaiderTheAnimation Android Kikaider: The Animation]]'', voices the tokusatsu incarnation of the character here. Really, it's surprising that so many ''were'' the original actors.

* DemotedToExtra: [[Series/KamenRiderDecade Decade]], despite having the specific role of PlanarChampion, his appearance here has him as FakeShemp in a quick cameo like many of the past Riders. Also, there is no hint of Ryotaro and Hana, the main human characters of the original ''Den-O'' series.

* ChekhovsGunman: the ManInWhite who threw the OOO Driver back to Eiji.
* ChekhovsGag: at the beginning of the film, OOO fights three Imagin, believing them to be Yummy even though they don't bleed Cell Medals, but Ankh arrives and tells him they're not Yummy at all. [[spoiler:Yet Ankh was later able to procure a ''Core'' Medal from another Imagin: Momotaros.]]

* TheSlowPath: one of the two {{Tagalong Kid}}s [[spoiler:gets left behind in the past. He would grow up to become the Shocker scientist who removed the Double Riders' brainwashing, and, shockingly, his best friend's father.]]

* ActingForTwo: HiroshiMiyauchi comes back to voice both Series/KamenRiderV3, and Series/KaiketsuZubat.

* FakeShemp: Inevitable, given the number of past heroes and villains going back to 1971. Aside from the main stars, almost all of the Kamen Riders appear in-costume only and voiced by replacement voice actors. It also affects many of the villains, along with the other four "allies of justice", though HiroshiMiyauchi returns to voice [[Series/KaiketsuZubat Zubat]] as well as [[Series/KamenRiderV3 V3]], and Creator/TomokazuSeki, who previously voiced {{Kikaider}} in ''[[Series/AndroidKikaiderTheAnimation Android Kikaider: The Animation]]'', voices the tokusatsu incarnation of the character here. Really, it's surprising that so many ''were'' the original actors.