Proto-Drive. He defended the world during the Global Freeze, and he got no thanks... and the world never even knew about his heroics. His motorcycle, while silhouetted out, is the same type of motorcycle used by Machine Chaser... implying there's a connection between the two, and that Proto-Drive isn't dead. And he isn't. Proto-Drive isn't dead, He's Chase. Seems the other Roidmudes did something to him to make him forget.
#4: Shinnosuke was rather annoyed with Dream Vegas' first use of his finisher, and thus was reluctant to use him. Then comes the case with the Paint Roidmude, and he finds out that, just like him, Vegas' partner got injured during the Global Freeze. Combines with Heartwarming when Shin makes his effort to go out of Tridoron during the rain and shield Vegas from getting soaked.
#11: We see that Mr. Belt was really broken down by the death of Proto-Drive, and then nearly lost his second comrade in Shinnosuke. He rages at Shinnosuke for being so reckless.
#13: Seeing #017 and #018's numbers hovering around while the younger is calling for the older just before they were shot down by Mach somehow feels a bit tragic.
#15 is titled "When Will These Feelings Reach You?", supposedly about Kiriko's feelings towards Chase's after #14. Unfortunately, they won't and never will get through to him, not if the other Roidmudes have any say in the matter.
And what about the main case investigated in the episode? We now know that Lira, the victim of the week, was a suicidal actress whose life was saved by a young fortune teller. They fell in love and stayed together until her manager decided to meddle with their love life. When he was uncomfortable with this and tried to break up with her because of that, she tried to kill herself again, but ended up killing him. That memory was absorbed by a Roidmude, who protected her for an year. By the end of the episode, the huge punch: they found out that one of his tarot cards was missing: the world, which means Eternal Love when related to feelings. She breaks down in tears and we see the card under the sea. So, yeah, they knew this would be a powerful scene that would send the world under a sea made of tears.
Akie's story from episode 18 and 19. Her only living family member, her brother, was framed as Judge and eventually was murdered by the real Judge. This left Akie alone and under scrutiny by the media and society. She eventually found happiness when she fell in love with a young man and they were to marry but when her love and his family found out what happened with her brother and him supposedly being Judge, the wedding was called off, leaving her devastated and running to Tachibana for comfort. This caused Tachibana to blame himself for not stopping the real Judge and wanting to do anything in his power to stop the Judge, which attracted a Roidmude attention and who synchronized with him and evolved into the Judge Roidmude.
#20: 072's death by the hands of a sadistic Medic. Shinnosuke's shocked reaction tells it all. Sadder is 072's final request: to spare Kyu the pain of knowing his friend was murdered that way, he had Shinnosuke tell Kyu that he eventually went berserk again and had to be taken down. In the end he'll be remembered as just one more evil Monster of the Week by everyone except for Shinnosuke and Kiriko; he'd rather that than have Kyu suffer.
#21: Medic gets back at Shinnosuke for harming her in the last episode by turning all the Shift Cars against him.
Chaser using both Funky Spike and Burning Solar against him.
Movie War Full Throttle:
Lupin shoots Mr. Belt, seemingly killing him.
Shinnosuke: Mr. Belt!
#26: After Chase breaks Shinnosuke's arm in a fight between Drive and Heart, Heart tries to bring Chase back, although the latter still has doubts. Realizing this, Heart reluctantly leaves Chase. It's particularly heartbreaking when Chase calls out to Heart, clearly anguished that he'd hurt his friend.
Heart: I came here to bring you back, but I've changed my mind. There's no point in saying anything to someone who hasn't made up his mind.
#27: Gou finally fesses up about why he's so intent on destroying every Roidmude. Professor Banno, who created the Roidmudes, which led to the Global Freeze and the subsequent deaths of many people, is Gou and Kiriko's father. Gou feels the responsibility falls on him to make up for his father's mistake.
When the people who 050 attacks are hospitalized, Otta - who was previously undercover with Rinna to draw said Roidmude out - is among them. We hear Rinna crying and pleading for him to wake up, and it is heartbreaking.
#32: The trailer, which shows Type Formula getting hit from a blast from Freeze. You hear the explosion as it hits Type Formula and then... the music comes to a total stop as Shinnosuke falls to his death. Not helped by Kiriko's anguishing screams...
In the actual episode, it's more sad to know that both Shinnosuke and Belt-san didn't even go down fighting. Normally in shows like these, heroes would often try to put a good fight before being defeated. Here, the duo don't even get a chance to retaliate and got struck down the moment they let their guard down.
#33: Everyone pretty much breaks down from Shinnosuke's death. Genpachiro swears in a tearful manner to try and take down Makage for Shinnosuke, Kiriko shuts herself in her home, and even the Chief is on edge, snapping at Nira for speaking of replacing Shinnosuke.
#34: It turns out Eisuke Tomari's murder wasn't at the hands of a Roidmude, but at the hands of a fellow officer who was jealous of his skill. Worse, Shinnosuke's dad had actually tried to help Nira because he believed he had it in him to be a good cop. Such a petty, selfish motive ended up being the reason Shinnosuke lost his father.
#36: You know the certain scene that comes across narmy when Nira was barking like a dog at Shinnosuke? Once you look back and understand the scene more in context, the part when Nira brags about putting down Eisuke like a dog in front of Shinnosuke and barks like a dog to rub it in further, it becomes less funny once you see something dripping on his cheek: tears. Holding back his own emotions while Nira mocked his father and Yukari's life in danger, making you think he's about to pull his gun out and shoot him in cold blood... which thankfully didn't happen.
#37: It's easy to miss it due to it being a Freeze-Frame Bonus, but it's a little sad to see 072's picture crossed out on Rinna's Roidmude Hit List
The status of the Roidmudes is pretty sad if you consider it from the point of view of someone like Heart. There were once 108 Roidmudes, and now there are only 45. That's less than half of their original number, and Heart considered all of them his friends.]
#40: Gou's finding out just how horrible a person his father really is and that he was tricked into helping Banno achieve his own goals.
Made worse in #41 where Banno refers to Gou as a research subject and that he only saw a family as another group of people to rule over.
#42: Medic is able to achieve her Ultimate Evolution only for her personality to be wiped out thanks to Banno's interference.
Even though he's been constantly humiliated and belittled by Medic, Brain is upset at what happened to her and his hand in causing it, actually shedding tears.
#43: Heart watches Banno abuse another Roidmude and has some nasty flashbacks to when HE was being tortured. He can't attack Banno, since he wants to protect Medic, so all he can do is try to shield the poor, downed Roidmude with his own body, looking completely broken as a result.
In addition, this moment is sad for a very subtle reason. Brain was almost the Last of His Kind, and with his death along with 087 and 107 soon after, only a few Bat-Type Roidmudes (035, 059 and 101) remain, and they're all Reaper Legionnaires brainwashed by Banno.
Heart and Medic dragging themselves over to Brain, just barely getting a hand onto him when his body and core disintegrate.
Brain starts listing off his good traits but dies before he can say the last one, with a desperate Heart telling him to finish what he was saying.
Chase experiencing the pain of heartbreak.
#45: From the trailer alone. Four words. Kamen Rider Chaser dies.
Chase dies protecting Gou, despite the fact Gou hates him. Chase gives Gou his Driver's License and Signal Bike.
Chase: It would be a shame if they were lost in the flames...
Seeing Chase's Core...and how it explodes. There is no return for Chase.
A subtle one earlier on, given what happens to Chase: Mach refusing Chase's help and snapping at him to mind his own business.
#46: Heart is the last of his kind.
Medic did try to save 081, 101 and 105, but finds out she no longer has her healing powers after being freed from Banno's tampering.
Medic not getting a chance to apologize to Chase before he died.
Even if you have endured the moment in #45, nothing could prepare you for when Kiriko finds out about it.
Gou realizing that Chase was his friend and that he was too stubborn to admit it. Yuu Inaba's acting is what really sets it into Tear Jerker territory. You can hear every bit of anguish in his voice as he talks about Chase
Medic dying, followed by Heart and Shinnosuke grieving. Not to mention she was the last Cobra (Even 006's body was destroyed).
# 47: With Heart's passing, the Roidmudes are officially extinct. This sadness goes so much into detail.
For one, Heart dies, being denied his final battle that he wanted so much.
Heart proclaiming Shinnosuke his one and only human friend before he dies.
For another, the Roidmudes are now extinct. While it's sad knowing that the last few Roidmudes to pass were some of the nicest, it's sadder knowing that, because of their past actions and how their redemption is only known to a select few, it's highly probable that the Roidmudes will forever be known as humanity's enemy, with the same amount of vitriol that Gou once had. This might get mitigated with Mechanical Friendship, a novel Kyu made about his time with 072, though.
Especially with the knowledge that they could in fact live along side humanity as 072 and Chase proved
As he's dying Heart tearfully begs Shinnosuke to remember the Roidmudes as a species who just wanted to live on the Earth
Krim's final goodbye to Shinnosuke and the others as he seals himself, Drive's tech, Mach's tech and the Shift Cars under the Drive Pit so the Core Driviars won't be ever misused by the wrong hands again to the music of the Orchestra version of Surprise Drive. While chances are they will appear again in future movies and there is a chance that maybe someday the world would be ready for this kind of technology thus there would be no need for the technology to be sealed away, this is still a bittersweet moment for everyone.
#48 gives us the ending credits, which features every important scene in the series, the debut of each Riders and their forms, the Roidmude leaders and Banno, the interaction between each characters (including Kyu-072), all of them are Awesome and Heartwarming. However, near the end is the deaths of Brain, Chase, Medic and Heart, which will make you flooded with tears.
Kiriko has it kind of rough. Every person she's ever cared about has turned out to be evil, turns evil or gets killed. Her own brother falls victim to this, and it's hard to see how she can keep putting up with this.
From the Kamen Rider 4 DVD special: Gou is killed twice (once by a monster pulling a Taking You with Me, second by being Impaled with Extreme Prejudice by another monster), leaving Kiriko sobbing over his body. The third time, Shinnosuke intercepts the fatal blast. Kiriko and Gou are quickly at his side, and he manages to choke out Kiriko's name before succumbing to his wounds. Good thing Time Travel is involved, and Shinnosuke's stuck in a "Groundhog Day" Loop.
The movie finally canonizes what happened during Faiz's ending: Everyone died, including Takumi, all except for Kaidou. Due to the twisted timelines, however, Takumi was revived again. He was the one responsible for all the time loops, due to not wanting anyone to die. He finally resolves to end his life for good by ending the time loops... Preserving the fact that his final smile as he died wasn't a lie.
Shinnouske's own SON ends up betraying him in the near future, in the sense that he believes Drive is the cause of the Bad Future.
The look of pure anguish as Shinnouske is forced to kill Mr. Belt.
It is implied that the Paradox Roidmude had killed Eiji in the future in order to gain his gear and steal his identity. Imagined what Shinnosuke is feeling at the time, not only was he was deceived and set up by Paradox and had to Mercy Kill Krim to prevent him from becoming corrupted, he was helping the murderer of his future son the whole time. While chances are Eiji's death is undone thanks to the fact that Paradox present and past self was destroy thus preventing the circumstances that could lead to his death in the future, it doesn't make it any easier.