Information from the Chrono Trigger Ultimania, which also has information regarding the DS rerelease (please note that I translated this with a machine, and for any super important parts I will ask some human friends if they can kindly read it and translate it proper). The End of Time is a small island-like space, not connected to the rest of space-time. Only three people can travel through time together at once, as four or more would disturb the force field of the dimension.
Lucca
Time travel rules
I've been to a strange place. A small space like a solitary island in space-time, floating apart from all time...A world in between called the farthest end of time. An old man who seems to live in this strange places says that this is where travellers find themselves when they get lost. If four or more people born in different eras enter the space-time distortion, the force field of the dimension will be disturbed, and they will be blown to the farthest land. Hmm...I thought I understood a bit about Gate, but there's still a lot I don't know. Come to think of it, what caused the gate to appear in the first place?
The End of Time exists outside the flow of time.
A place out of the flow of time, where those who become "lost children of time" end up. It is familiar with all eras, and in addition to the present and the future, it can also go to the dimensional arena.
The party is blown away by the power of the Chrono Trigger, and are sent to just before Crono disappears in a moment of frozen time.
Go back in time and rescue Crono
When you reach the top of the mountain, the party is blown away by the power of Chrono Trigger 1 to just before Crono disappears after being attacked by Lavos at the undersea temple. Since time has stopped, no one will respond if you talk to people there, but if you examine Crono, it is possible to replace him with a Doppel Doll. After this, when the party returns to the mountain of death, Crono is revived, and the party automatically moves to the End of Time.
Lucca talks about how Queen Zeals Black Dream (the Black Omen?) casts a shadow over space-time, both the past and the future, and that 14,000 years in the future Zeal and Lavos will destroy the world. She then says that she and her friends will stop them from doing so with all their power.
Lucca
End the eternal dream!
Black Dream - It is a dream that Queen Zeal, who has been fascinated by Lavos, continues to see in ancient times and never wakes up. Apparently on the day when the civilization of the world was destroyed and people lost their magical powers, it is a nightmare in a blind alley that spans the space-time of the past and the future without casting a shadow over the world. It keeps waiting. A time when a god and a monster wakes up from it's 14,000 year slumber to bring about the "Day of Lavos"...Of course not! The power of science, the power of magic, the power of primordial power, and the power of frogs! And Crono's car has returned - I'll hit you with all the power we have and wake you up from that bad dream! I'll let you know it's not eternal life!
Lavos not only steals the energy of the planet, but also the DNA and memories of all of the creatures that live on the planet. While Lavos sleeps, it collects the best parts of other creatures to send its evolved alter-ego to another planet (I'm not sure if this is refering to Lavos' own alter-ego or just spreading its young across the cosmos).
Marle
Stealer of Life Memories
I finally got it. What did Lavos' identity come for and what did he do from the Primitive Age? On that day when the dinosaurs were destroyed, Lavos fell from the sky and settled on this planet. He was a parasite in our world, sucking up minutes...but that's not all. Lavos has absorbed even the creatures that have become stronger in battle according to the laws of the land of all creatures living on the planet. While I'm sleeping, I'm collecting only the best parts of other creatures and I'm trying to send my evolved alter-ego to another planet! I can't let that happen! Crono, everyone...let's end it here! Let's take this planet back into our hands!
The dimensional vortex appears in the past, present and future, and entering it takes you to another space which doesn't belong in any era.
Dimensional Vortex
A strange gate that suddenly appears in three eras: ancient, modern and future. Crono who enters the gate arrives at a space that does not belong to any era. What awaits them in the deepest part of a different space where they are led as if being called by something?
Robo has a space-time gyro that lets him tell the time and what place it is, but it doesn't work in the dimensional vortex. Within the dimensional vortex, all eras mingle together, and there are implications of creating branching timelines through time travel.
Robo
Shoot the split shadow!
The ancient, the modern and the future - the three-dimensional distortion that suddenly appeared is a tremendous deshita that far exceeds our common sense. In the distortion, my space-time gyro is completely useless, and I can't identify the time and place. Yes, rather, it's a space that should be called nowhere, where all the eras have been mixed together like a broken puzzle. Awaiting in the depths are three shadowy deshitas who live in the kingdom 1000 years old, which is the starting point to save the future of the planet from the threat of Crono, Marle, and Lucca Lavos. Another modern phantom with countless branches created by the alteration of history.
The gate in the bucket that leads to the Day of Lavos also leads to another dimension. Crono and his friends jump into the bucket to confirm the identity of the terrifying signs similar to to Lavos emanating from there.
It seems that the gate that was connected to the Day of Lavos, a bucket placed at the End of Time, was also connected to another dimension. Crono and others jump into the bucket to confirm the identity of theterrifying signs that are similar to Lavos emanating from there.
Magus says he and the heroes will transcend time and space to defeat Lavos, and contemplates the different possibilities which they create, and wonders if they vanish if they choose one. He then thinks about how all of these possibilities likely exist as innumerable worlds which overlap each other in a space-time dimension, and how on some worlds Lavos won, and on other worlds there may be creatures even worse than Lavos. No matter which world, he swears to fight the threat, no matter how harsh his fate may be.
Magus
A world where future threatens to sleep
We will transcend time and space to defeat Lavos, who landed on this planet in ancient times and will bring the fate of destruction to the future. It's just an act of grabbing one of them.
If so, will the other histories that where not chosen by us disappear? I don't think so. The world of "innumerable possibilities" will continue to exist overlapping with this world in a space-time dimension that is different from this world. There is a world where Lavos could not be stopped...or, there may be other worlds trampled by more troublesome monsters. In any of them, I will fight and fight. No matter how harsh my fate is, I will definitely...