Final Fantasy V introduces a very affective system to incorporate and compliment the classic Final Fantasy battle style. This system is called the Job System and allows you to train up your characters in various jobs to gain new skills to master. What makes this unique is that you could give each of your characters different number to jobs to change the way you approach the game. For example, you could have an all-physical fighter's party in which you could make 4 knights or 4 monks. Or you could make things challenging for yourself by creating 4 white mages. The possiblilities are almost endless. You will start with a limited number of jobs (from the crystal), but You will find new jobs on the way and each one unique and different.
There are so many skills that can be learnt from all the jobs and these can be combined to make your ultimate character. Want to create a Knight that can cast black magic? You can with this sophisticated system and is something that you couldn't do before in other RPG's before it.
Apart from the new job system, the basic battle system is identical to its predeccesor but this is not at all a bad thing. Battles are quick, fluent and do not drag on pointlessly. The summoning time is short too, something that people had complained about in the PSX Final Fantasies.
Storywise, some people may argue that the story is full of cliches because it involves the over-used sense of young adventurers battling against a dark foe to save the world. But I argue against this case because what RPG has NOT had a impending evil threatening the safety of the world? The story in FFV may follow traditional styles of RPG stories, but the story is incredibly in-depth and engaging all the same.
There are no secrets to gain from completing the game and is applicable to the majority of other Final Fantasies and non-Square RPG's. However, this does not stop you from enjoying the game if you play it again. As mentioned in the Gameplay section above, giving your characters jobs in different combinations and situations makes this game very fun as you can create your characters how you want them to be.