Kuuga's bike-on-bike battle with Go-Badaa-Ba. Or really, any time he uses Bike Fu, because he's one of the best Riders at using it.
Any time he masters a new form for the first time is a memorable moment.
Transforming to Mighty Form after a rousing speech about what he's decided to fight for as a church burns down around him, Ichijo, and the Grongi they're fighting. It was the first time he made his legendary Badass Boast, and when he told everyone to witness his transformation, we ALL listened.
Yusuke: I fight to protect people's smiles, so that nobody will have to cry! So please, witness...my transformation!
Learning Dragon Form's strength in the form of both its acrobatic ability coupled with the Dragon Rod and its accompanying fighting style focused on quick strikes and deflections.
Mastering Pegasus Form by snatching the Monster of the Week's stinger-like projectile out of midair, then one-shotting it with his own weapon, the Pegasus Bowgun. The Grongi screams like a little girl in fear.
The emergence of Titan Form features Kuuga no-selling the monster's explosive spitting attack while slowly advancing on it, stopping the last one with his hand, then running the bastard through with his sword.
Episode 35. Kuuga delivers an unbelievable smackdown to Go-Jaraji-Da, a monster that really, really deserved it. Once he finds the Grongi in the hospital, Yusuke transforms into Mighty Form while running at it, tackles it out the window, and then just starts pounding its head into the pavement, screaming the whole time. Once it starts to fight back, he summons the Gouram and then rams it, driving Jaraji all the way to the lake on the front of his bike. En route, Jaraji tries to kill Kuuga by stabbing him close-range, but Kuuga sees it coming and switches to Titan Form, shrugging the attack off. When he gets to the lake, Kuuga comes to a screeching stop, throwing the Grongi into the water. Then he draws his sword and slowly walks toward Jaraji (who is whimpering in terror at this point), silently transforming to Rising Titan, then slashing the Grongi and finally knocking it on the ground and finishing it off with a brutal Rising Calamity Titan, after screaming during that curbstomp as well.
It also dips into Nightmare Fuel, as the scene is meant to draw concern for Yusuke's psyche. Up until this point, we've never really saw Yusuke actually get angry. He's always nice and likes to make people smile. Then he got pushed too far.
Ichijo deserves a mention for his sheer dedication to his job, even when badly injured. He also is one of the only normal humans in the series to take out any Grongi.
Sugita and Sakurai deserve mention as well, as they manage to pursue and kill one of the remaining, most powerful Grongi without any assistance.
Episode 16: Kuuga does a finishing move on a truck so hard that it somehow kills the Grongi driving it!
Up until his confrontation with Zu-Zain-Da, Yuusuke's Rider Kicks were mostly incidental at best (a simple side kick or an impromptu jump kick). However, after Zain defeat him, he practices his Rider Kick until it becomes the memorable flying side kick that we all know and love.
While it's played for horror and somewhat sad, Kuuga's final transformation into Ultimate Form and battle against N-Daguva-Zeba is also one of these. The lack of music with the only and the feeling of intimacy with the only ambience being the cold wind blowing makes this scene feel less like a true final battle between two warriors. Godai stares down his final opponent in the snow. Both combatants at their strongest. Their powers can barely even hurt one another so they both resort to a fistfight. What comes is truly shocking to any Kamen Rider fan. Kuuga manages to destroy Daguva's armor so Daguva actually aims a punch at the Arcle (Kuuga's belt) breaking it! Despite both being left in human form powerless, they both refuse to let up so they get right back up and resume fighting! Both are running on the last of their strength, Godai pushes through while Daguva continues to laugh at him. Soon enough the snow is dyed red by their blood as they clash one last time. All falls silent. The characters later point out anyone else would have given up, but not Yusuke, not when everyone needs him so badly.
When Godai appears as Kuuga in Wizard's epilogue, he is capable of using Rising Ultimate (a previously Decade-only final form for Kuuga) without any issues, unlike his AR counterpart Onodera, who struggled with Rising Ultimate the first time he used it.
