Creator Breakdown: According to Masato Kato, the head writer for Chrono Trigger, Radical Dreamers was influenced by feelings of frustration he had harbored while working on the previous project - this, he claims, influenced the darker tone of Dreamers and subsequently Chrono Cross when compared to the (relatively) lighthearted Trigger.
Doing It for the Art: The reason the game took the controversial route of being so different from Trigger is that the developers felt there was no point in making the same game twice. The game ventured in a completely different direction for the sole reason that its creators felt Chrono Trigger was so good that trying to replicate it would merely be redundant. Both written and directed by Masato Kato, the head writer for Trigger, Cross features a more personal and ponderous narrative and explores the themes of its predecessor from very different perspectives; the game incorporates a number of incredibly ambitious ideas (such as an absolutely huge roster of playable characters, complex and branching storylines, and high-minded philosophical themes) that few, if any games have attempted since. By far the most done-for-the-art aspect of the game, however, is the soundtrack: even though he had just quit Square Soft, Yasunori Mitsuda was hired to score the game simply because Kato considered him an indispensible part of the Chrono formula. The decision to compose two different songs for each area—one for each dimension—was made at the last minutes, simply because Kato and Mitsuda thought it would be a good idea. The singer and lyricist for the ending theme, a relatively obscure artist by the name of Noriko Mitose, was chosen despite Square Soft PR's wishes for a more popular and marketable singer, simply because her style was deemed "right" for the game.
I Knew It: This game was created because of one persistent nerd rumor: Schala Lives! ...as three different people at the same time. There's the "original" Schala stuck in the Time Devourer; Kid, Schala's "clone-daughter"; and Harle, who is an echo of Kid. Oh, and at the end, you get to free the original Schala, assuming you paid attention during the last dungeon.
Jossed: The new ending and storyline in the DS version of Trigger jossed some fan theories very, very hard.
No Export for You: Chrono Cross was never released outside of Japan and North America, which makes the continuity nods in the DS remake of Chrono Trigger just plain annoying for everyone living outside those two particular regions. The more general references to Radical Dreamers are also beguiling for everyone outside of Japan, and probably even many people in it.
Urban Legend of Zelda: This game has one of its own. Thanks to some erroneous text from a Brady Games guide, players were led to believe that the Wraith monster would sometimes drop the Ghetz' Shirt, an armor that increased several stats in exchange for giving the wearer several status ailments.
According to the developer's room, Zoah's helmet hides his secret identity as a prince of a certain country to the north who's watching over the party. Unfortunately, the scene that's supposed to hint at his true origins was never implemented.
Like many PS1 RPGs, there is a huge Info Dump near the end of the game as the writers tried to get their plot points across before the Cosmic Deadline hit.
Working Title: The game was called "Project Kid" at one point while in development. This was actually a thing in the game (see the entry in the main page).