My first time playing I wasn't a big fan of this game, but after picking it up again, this might be my new favorite FF.
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The controls in the game are really easy to learn and use. Everything is quick access with almost no load times in between screens. Square did a good job in the Overdrive system (Similar to past game's Limit Breaks) and offers little "mini games" to play in order to maximize your damage ranging from match the buttons to hitting X at the right time. Menus are done very neatly with a nice color scheme and they offer a preset organization option that helps you keep everything in line. The battle system is nice and it offers a new kind of experience in this game by allowing the player to change characters mid-battle. One of my favorite additions in this game was the sphere grid. Its nice to be able to learn lots of different abilities with all your characters as well as not specifically limiting their stats due to classes.
Graphics
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The graphics in the game are phenomonal, even today. Going off graphics alone this game still ranks in my top 5 because of how easily it can transition between gameplay and CGI. I personally enjoy the character designs in this game because they are so different with each character. The CGI sequences are amazing. There is so much detail in everything that is happening that it helps suck you into the story that much more.
Sound
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The music in this game is absolutely outstanding. Starting from the beginning with the first scene, you hear one of the theme songs, "To Zanarkand", while the main character begins his narration and it immedately pulls you into the story. Every scene is accomanied by some kind of amazing score that just digs deep into your heart and pulls out emotion. I would even consider buying the soundtrack to this game if you are a big enough Final Fantasy fan. Nobuo Uematsu is a genius.
Value
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In my opinion, this is one of the best games on the PS2. It offers a heart-wrenching story, an amazing cast, phenomenal music, and good replay value. There isn't a lot of change for each time you play it but there are definitely a lot of things to do including obtaining all the celestial weapons, hidden dungeons and bosses, and the Blitzball minigame (kind of like underwater soccer).
I love this game!