Chrono Trigger surpassed other RPGs in all respects of its time. Featuring the unique dimension of time travel, Chrono Trigger allowed the player to interact in 5 full worlds, surpassing the 3 worlds of Final Fantasy IV and V, and the 2 worlds of Final Fantasy VI. It also set in stone the precedent of the 3-party system, which was earlier used in the Seiken Densetsu series. Chrono Trigger also features Yasunori Mitsuda's first OST, and he clearly creates some classics in this game. With all these features and much more, Chrono Trigger is an everlasting classic.
Gameplay 10/10
The first corkscrew thrown in Chrono Trigger is the 3-party system. After a series of 4-player RPGs (Final Fantasy IV being the exception with 5), there are only 3 members. Also, their HP and MP cannot exceed 999 and 99, respectively, thus adding more limitations on the battle system. Sounds difficult? Well, not really. As the characters level up and learn more skills, certain ones can be combined as "double techs", and eventually "triple techs" for even more damage. One must use each wisely for maximum effect.
Music 9/10
Yasunori Mitsuda's debut is not a shabby one; he produces many fine masterpieces in the album. The Chrono Trigger theme is perhaps as recognizable as the Final Fantasy Prelude and Overture by Nobuo Uematsu. There are a few songs that are not by Mitsuda; the boss battle is one such piece (composed by Noriko Matsueda, and arranged by Nobuo Uematsu). There are, of course, a few flops, but it is overall very excellent and pleasurable to listen to.
With time travel, one can't expect a mediocre storyline. Chrono Trigger's story is truly a masterpiece. There have been numerous claims that Chrono Trigger relates to Jesus and the Bible and whatnot, and from the evidence it seems pretty true. On the surface, Chrono Trigger seems to be a nice, little kids' story about a group that time travels to save the world. But when one explores deeper, there are a whole new level of themes and motifs to be discovered. And, there's Spekkio. End of story.
Final Dungeon 6/10
Well, I suppose the score would be better if there actually was a final dungeon. But there isn't, so I'll use the Black Omen, which is pretty much just a straightforward dungeon. Really cool last dungeons are reserved for the Final Fantasies and Xenogears, apparently.
Final Boss 8/10
Well, it depends on when exactly you fight the final boss. Due to Chrono Trigger's unique time jumping, you can fight the final boss in a variety of places. And in each different place, it's slightly different, though the last few parts are the same. It's quite challenging.
Replayability 10+/10
11-15 endings to get (depending on how you count them). What more support do you need? Getting to Level **? Destroying that goddamn DragonTank with Luminaire? This is a keeper.
Overall 10/10
I don't think that I can say this enough: Chrono Trigger is a classic. Nice little adventure story for the kids, way deeper levels of meaning for the older gamers. Multiple endings, time travel, subquests, music, what more do you need? It's all in Chrono Trigger.