When I first played this game on the PlayStation 1, all those years ago, I was captivated by the realism the game gave off. Skip forward about eight years and when I gave it a replay the terrible graphics gave me a headache. But there was one thing that this game had that I've not seen in many games and that was the gun blade. Squall's signature weapon was what drew me back into the game, the ability to increase the power of your regular attacks by pressing the R1 button immersed me into the game. For me this is the reason why this game beat out both final fantasy 7 and 9. Granted, Final Fantasy 7 had the buster sword, but how weird the characters looked threw me off. Anyways, be mindful that this review might be a little biased due to my gun blade favoritism. 

Graphics:9
The graphics of Final Fantasy 8 really drew me in over any other of the final fantasy series I have played(7,9,10,11, maybe 3(remake version for sure)). I mean compared to FF 7, where the characters had square blocks for arms, FF 8 looks a lot more realistic. Now it's nothing compared to today's graphics, you'll probably get a headache from playing the game if you're not used to it. However, it was good for its time. Which is why I gave it a 9.
Sound: 7
I'm not really a good judge of sound. Going to be honest here. My criteria for judging the sound basically revolves around; is the background music annoying, does the music suit the mood, are the sound effects clear and not a mess. Generally I felt that it was pretty good, but not being well versed at judging this sort of thing, I can't bring myself to give it too high a score.
Addictiveness:4
I really do like this game, however it's not addicting. The themes are interesting and the story is good, the gun blade is great. But none of those things are enough to pull you back for a replay. It's a good game to get through and beat, but the grind sucks. The game has this function where you have to gather magic, you can't just cast magic with mp. Meaning limits to how many times you can cast your favorite spell, meaning you have to grind just to be able to cast your favorite spell. Not fun at all. There is this card mini-game that is pretty good to play, but if you're looking for fun mini games, FF7, chocobo racing, or FF9's card game is better.
Story:6
I really liked the story in the beginning, two gun blade users are in a rivalry with each other and it seems that Seifer is your biggest enemy. You Squall Leonhart, or really whatever you choose to call him, I named him Bob once, yeah. You're a student in an Academy that trains professional soldiers called SEED's. And to me it was very easy to immerse myself into the story as a person seeking to become a seed, trying to pass the examinations, and yes there are exams that determine your seed rank, which determines your stipend. But this all becomes kind of irrelevant as you progress through the story. The story was pretty confusing to me, the love triangle, the plots by the witch, how the headmaster knew the witch, what exactly did Laguna(a gun wielding character you play for a bit in flashbacks) have to do with the main story, etc.
Depth: 7
There's a lot to do in the game, not anything groundbreaking but quite decent. Aside from the main story you can play this card mini game that's sort of fun to play, collecting rare monster cards and such. You can wander around the Academy, drive in a car, ride a train, and play various minigames located throughout the story. It's nothing special though, compared to FF7's chocobo raising and races or FF9's mini games. 
Difficulty: 5
It's hard initially to figure out how the game works. However there are in game tutorials, which were rather annoying to me when I replayed it. The difficulty is simply put in saving(always remember to) and grinding. Which is why it's got a difficulty of 5, if you hate grinding, hate killing the same monster or having to fight the same monster to try to get that spell you've been looking for. I mean it takes hours of grinding sometimes to get 99 of a spell that you want like double. It's annoying, because you have to cast absorb or whatever you call it, every turn. But if you can get over that, the game's pretty easy.

I completely agree with your review, especially with your view on the addictiveness category. Grinding is such a pain in this game and that's one big reason why I don't like this game. I also think you added a decent amount of detail to the whole review as well. Overall, I think you did a good job.