In the Geats-Gotchard crossover movie (Kamen Rider The Winter Movie: Gotchard & Geats Strongest Chemy★Great Gotcha Operation) it's revealed that Ace once had a dog that was hit by a car. The dog comes back in the form of a spirit/Chemy.
Debatable. The epilogue is very hopeful and victorious but only after the heroes fight through a very sad ending. This doesn't include the post-season movie. I haven't seen it yet.
One character becomes massively depressed during the course of the show and when it became too much, he decided to deal with the problem directly. He bounces back from this.
Despite this series being filled with neon laser guns, one character is suddenly shot and killed by a regular handgun with no warning. There is also a heavy use of blood during this scene.
After an episode ends, a screen is shown with narration that explains a rule of the Desire Grand Prix. This is followed by the preview for the next episode.