Overall: This game is what it is. It is a remake of Final Fantasy I (Nintendo Entertainment System), and Final Fantasy II (PS1). The story is the same, and almost everything is improved.
Graphics: Decent graphics, reminiscent of the originals, upgraded to be on par with other games on the  Game Boy Advance.
Sound: The music is good, classic Final Fantasy fare.
Addictiveness: In this game, the story is what keeps me coming back. More on that later.
Story: Now is later. The story, at least for II, is amazing. I has a story, but it isn't as in-depth as II.
Depth: This game world is large, and has very much to do. There is a secret in both games that requires a set of button presses, and it unlocks a mini game for fun and prophet.
Difficulty: These games are difficult if you don't take the time to grind for Experience and Gil. These games are designed to require that to pad the game length. The mini game i mentioned earlier makes the game much less difficult, as it affords an infinite supply of items based on your performance.

True, you could play I first, but you wouldn't miss out on any of the story for II if you started out with that. Really, it's a matter of personal preference.