The first game operates on a battery due to time events and remote control interface. While you can replace it, eventually the battery will run out, taking your save data with it.
In the first game, several wild Robopon have too-small CPUs and are prone to violence, confusion, and going out of control. This is even worse when you remember they're sentient.
After Dr. Zero defeated Prince Tail's father, the King attacked him and left him for dead. Zero repaired his original body with cybernetics, and when he returns, he calls out Prince Tail for what the King did. The Prince is in total disbelief.
What happens to Princess Darcy in the first game, but more so its effect on Prince Tail. First Dr. Zero kidnaps Princess Darcy. Then Tail loses to Dr. Zero, losing his Legend1 title to the evil scientist. After training at Cherry Hill to win her back, Tail loses to Cody, losing the title of Legend2 to him. Then Zero traps Princess Darcy in a mirror because Tail lost to him and you. Cue Heroic BSoD. To top it off, even after you beat the game, you don't have to save Darcy.
Tail: I lost to Cody and lost everything that matters to me...
If you're playing an emulated copy, saving Darcy is impossible because the path to the treasure chest containing the Teardrop of Morris can only be opened with a TV remote.
The music in Poro Village. Even more so when you remember Underwater Creatures are an endangered species.
Robopon 2
In the second game, the music played in sad situations, which also doubles as the music for all fights with Nick D. and the alien storyline.
Dr. Zero's cyborg warriors are sentient beings... with kill switches installed. They explode after you defeat them. Blaze wonders if robots have afterlives, while Xardon drops his villainous act and soberly accepts his defeat—and asks Cody to keep on living. The third warrior, Tempest, asks you to save Dr. Zero from himself and says that he realized, through battle, how humans live.
Their combined form, Insector, acknowledges mankind's strength and thanks Cody for giving his life purpose beyond being a machine. He tells him to fight on and show him humanity's power.
in Poro Village. Even more so when you remember Underwater Creatures are an endangered species.