Final Fantasy was Square's final fantasy at the time: a farfetched idea and last-ditch effort to make some money. Thank goodness it worked, else god knows what 500 million people would do with their free time... Primitive it is, but open-minded (and hardcore) gamers shouldn't see that as an obstacle as they venture through the world of Final Fantasy.
Gameplay: 9/10
Contrary to what you may think, FF is pretty fun. Although not exactly open-ended, you can choose from an array of characters, make them strong, even upgrade them or not. And it's pretty fun slaughtering monsters left and right. Less talk, more rock. It's also pretty challenging it's first time through, as you'll always find yourself short of GP.
Music: 6/10
Well, it's the NES. But a 6 is pretty strong for the NES. Uematsu had to have been really inventive to work with this sub-MIDI thingy on the NES. He made some pretty rockin' pieces, Matoya's Cave the most notable.
Storyline: 2/10
Last-ditch efforts usually aren't extravagant, and FF is no exception. At the most, the storyline calls for you to bounce around from town to town, finding items to advance. Your characters almost never speak, and about 5 NPC's in the game are important. All your characters have absolutely no depth whatsoever, and the most evolved character would be Garland, and that's pretty bad.
Final Dungeon: 6/10
The final dungeon is pretty simple, but it has it's neat share of tricks, and you fight bunches of bosses on your way down too. It's not repulsive, just kinda average.
Final Boss: 7/10
The final boss can be quite a challenge. He's pretty fun to fight too. No special little tricks or cool moves really, or multiple fights, once again, FF was a last-ditch effort, and far from the extravagancy of future FF's.
Replayability: 10/10
There is an infinite number of possibilities your party can be in FF. All the different strategies possible is what makes this game worth it. It's implementation of jobs and classes were the basis and stepping stones to more, greater Final Fantasies.
Overall: 7/10
Well, for an NES game in a world of PS2 games, this fares quite well. 10 bucks says you're using an emulator for this, so unless your computer sucks (like mine), it shouldn't freeze up and erase all your data (like mine). It's definitely worth at least playing through once.