The best video game of all time? It's quite possible. It's certainly the best game ever released for the PS1.
Everything got a major overhaul from previous releases: graphics, backgrounds, design, mechanics, physics...in fact the only thing that needed no improvement was Squaresofts already stellar storytelling.
The minigames and optional quests, as well as characters, are all (as per usual) topnotch, but '7' had something else. Something, almost describable but not. Something in 7's story...something more than the enigmatic Cloud Strife, more then Sephiroth's dark connection to Jenova, something even more than Aerith made 7 a tale that was completely unforgettable. It will always hold a special place in the hearts of gamers, and will forever garner a justifiable respect from all of us as well.
All i can really say is, "All hail Bahamut!"