Kamen Rider the First

In 2005, Toei's latest entry in its Kamen Rider series, Kamen Rider Hibiki, fell victim to the conflicting desires of executives and storytellers.

Also in 2005, Toei decided to reintroduce the very first Rider to modern audiences. Thus, was born Kamen Rider The First, a theatrical remake of the first series.

As per the series, motorcyclist and college student Takeshi Hongo is nabbed by agents of the evil Shocker organization. Without Prof. Midorikawa to save him this time, Hongo is inducted into Shocker's ranks as a Super Soldier called "Hopper." He is instructed to kill all witnesses to Shocker's activities; however, after an encounter with a young woman and her fiancé, Hongo begins to resist his mental reconditioning. He is then double-crossed by Shocker and eventually leaves the organization; but then, he meets the fiancé, now named Hayato Ichimonji, AKA "Hopper 2"...

Followed by Kamen Rider the Next in 2007.

This film features examples of:

Actor Allusion: Hongo Takeshi as a Dogged Nice Guy only makes sense if you know that Kikawada Masaaya was also one in Pretty Guardian Sailor Moon.
Battle Couple: Snake and Cobra.
Calling Your Attacks: Averted by the Double Riders. Old fans can still name them by heart anyway.
Cybernetics Eat Your Soul: The Kaijin must undergo regular blood transfusions to avoid their bodies fatally rejecting their implants. Somehow, this trope is avoided with Hongo, but played straight with Ichimonji.
Darker and Edgier: Of the original series. Which was fairly dark to begin with...
Fake Shemp: Hideyo Amamoto posthumously reprises his role as Dr. Shinigami via archive footage.
~Hey, It's That Guy!~: Hassei Takano, AKA Kamen Rider Raia, is Ichimonji.
I Want My Beloved to Be Happy
Not My Driver: Spider's Modus Operandi at the beginning of the film.
Pragmatic Adaptation: The film renders aspects of the original series more realistically; for starters, rather than casting People in Rubber Suits as the Kaijin, they are now armored humans like the Riders.
Red String of Fate: Literally, with Haruhiko inadvertently getting hooked on an unraveling thread from Miyoko's red sweater as he tries to run away.
Remake Cameo: Hiroshi Miyauchi(Shiro Kazami/Kamen Rider V3 in the original series) as Tobei Tachibana.
Science Marches On: The film makes repeated references to a famous experiment involving ice crystals that has since been discredited (and most serious scientists thought was a bunch of New Age-y hippy crap from the get-go, anyway). In their defence, the film is just being poetic about it.
Took a Level In Jerkass: Ichimonji is noticeably alot more meaner than in the original show.
Tragic Monster: The Hoppers/Riders, as well as Shocker's agents Snake and Cobra.
Transformation Sequence: Averted. When Hongo spins the wheel on his driver, we cut to the already-suited Rider as he puts his helmet on. (You'll hardly even notice at that point that he is suited, as the suit is less spandexy than the Toku norm. While it fits the darker, more "realistic" film, Your Mileage May Vary if the look of the transformations is something you wait for with each new Henshin Hero.
What If: The film answers the question of what if Hongo didn't escape getting Brainwashed and Crazy.
- Answer: He's still gonna kick Shocker's ass anyway.