A must for any fan of Chrono Trigger... and almost any fan of RPGs in general.
While the plot was not directly related to Chrono Trigger initially, there are deep ties between the two that you discover as you progress. The game takes place on an archapelago somewhere to the south (if I recall correctly) of the lands where Trigger took place, and stays there for the entirety. There's no time-travelling, and it's definitely not needed this time around.
One of the great things about Cross was not only the number of playable characters, but you felt like you knew a good chunk of their backstories. They didn't feel tacked on or half-assed. You're able to choose three characters to use in your party at any given time (Serge/Lynx) has to be one, naturally) but can change it up pretty easily.
Speaking of combat, the system was a lot of fun though strayed away from Trigger's focus on group/pair attacks. While the game wasn't overly hard, some of the bosses certainly put up a fight.
The plot was fantastic, and added on to the already great story that Trigger presented us with. There were a lot of tragic elements that pulled at the heartstrings in Cross, but there were also a lot of humorous parts that balanced it all out nicely (usually involving Kidd threatening to kick someone's arse to the moon). Giving players three arcs to take early in the game was a nice touch, even if it didn't affect all that much about the game later on.
Chrono Cross is an RPG that begs the question -- if you're a fan of RPGs and you haven't played it, why the hell not? It's still a great game, and while the in-game graphics may have not withstood the tests of time too well, the plot, gameplay, CGs, and characters are all great reasons to pick the game up, either for the first time, or just for some nostalgia.