Saving Lucca's mother in Chrono Trigger is one of the most memorable scenes in an RPG about time travel and planetary parasites. This brief sidequest comes out of nowhere, requires you to do things you've never done before, and feels like a swift kick in the gut should you fail. You can see the whole thing play out here, but in brief Lucca (a party member) travels through a mysterious time gate to the day her mother became paralyzed. If Lucca acts fast, she can stop this tragedy and rewrite her childhood.
This is an incredibly tense sequence, and there are so many little touches that sell its emotional weight it's hard to know where to start. The music picks up slowly with an ominous siren transitioning into discordant, pulsating noise. Obviously, something's not right here, and any doubts are quickly dispelled when you see Lucca's mother slowly being dragged into the machine that's going to cripple her. This happens very quickly and in real time, meaning you have maybe a minute to figure out how to save her. I can't think of another instance where Chrono Trigger puts you on a time limit like this. Because the game hasn't prepared you for working under pressure, it makes what follows all the more panic-inducing.
Interacting with the machine reveals it needs a password. Crap! A note found in another room says the password is the name of Lucca's mom. Hooray? You do remember her name, don't you? No! It's Lara, and entering her name means hitting L-A-R-A on the SNES controller. This is another design not used elsewhere in the game, which can really trip you up if you're just mashing buttons on the controller to speed through the text boxes and stop the machine.
And did I forget to mention young Lucca is present the whole time this is happening, and she is completely freaking out? She is powerless to save her mommy - who is crying out for help - and can't do anything other than run around panicking. Failure here means exposing this kid to a horrible tragedy, one that will haunt her childhood, while simultaneously making the present-day Lucca feel all the more helpless as she is unable to rescue her poor mother again.
If you're like me, shutting down the machine is when you realize you've been holding your breath the entire time. The sequence's underlying genius is that all of its weight and impact hinges on the characters and your emotional attachment to them, not some giant boss with a million hit points. We all have a moment in time we'd love to do over, and while we'll never get that chance at least we were able to make the dream come true for Lucca and her family.