Little bit more than a fan service, but fan service nonetheless.
Crisis Core is rather odd piece of work because it lands right smack at the middle of Final Fantasy VII and it's bastard child.
There is some familiar stuff you will see that was in FFVII, in terms of story and location. However, all the new story they came up with links with Advent Children more than anything.
Well the main character of this game is the mysterious Zack. Playing as Zack is excellent for the fans because although he wasn't shown much in previous installments, he is much more familiar to the fans than Cloud in Advent Children. Zack's personality matches closer to the Cloud we played in actual Final Fantasy VII and that's a personality fans missed. In Advent Children, Cloud was already no longer the Cloud that was in FFVII.
So that's a good thing. Zack is a character that is easy to love, except for the fact he spurts out corny lines way too often to be embraced completely. But fear not, he is not as corny as trio of one winged freaks.
As for story overall, it is rather unfortunate that although many references to original FFVII is there, the actual story seems to focus more of connecting Advent Children into the franchise. It is most unfortunate because it means introduction of yet another pretentious character that gets way too self absorbed with themselves and literally talks poems out of their mouths instead of having some normal freaking conversation. The use of loveless act was in FFVII as well, but now they are taking things little bit too far. Does a man have to spurt that thing out every time he makes a conversation?
I don't know when this trend happened, (well actually I guess I do know, this is right around FF8), Square is focused too heavily on style when they create conversation instead of focusing on telling the damn story and portraying personalities of the character. To the point where that style gets in the way of telling the damn story.
Also another disappointing part of the story is that it spends way too much time on style rather than fine details of the storyline. The cut-scenes are too full of dramatic scenes with actions which tells little story, and you can't help but to feel the story is told briefly as possible.
Not only that, at times things feels out of place. Like in the middle of heavy battles that has your city crawling with enemy creatures, you end up having nice and relaxing conversation with new character you just met. It's good to introduce characters and such, but that's just horrible story telling. This kind of things keep repeating, like you are chasing after someone to capture, but you fail and falls to a pit. After you wake up, it seems our main character Zack have forgotten all about the mission and acts like he has all the free time in the world, and starts going out on a date, etc.
And then there are those coincidences. Is the only way Aerith can meet guys is falling from the roof and crashing down on her flowers? I mean that's okay way to make characters meet each other, but to have one character experience extreme situation like that twice is too much of a coincidence, and too much of coincidence is ALWAYS a horrible storytelling.
Perhaps the worst part would be the inconsistent personalities of characters of original game. It's not a huge difference, but many returning characters are a bit different from what you expect. Especially Sephiroth. If you remember original Final Fantasy VII, Sephiroth was actually nice guy before he went little insane. He was rather polite and knowledgable and kind enough to explain things to you. In Crisis Core however, he starts to sound like a little prick. No wonder his friend tries to kill him while practicing.
To put it simply, Crisis Core has too many flaws to be considered a good story. However, if you liked Advent Children and Dirge of Cerberus, this should be your taste. If you are like me who hated Advent Children and Dirge of Cerberus, then you will accept Crisis Core as what it is. Another vain attempt to justify Nomura's abomination called Advent Children but a nice fan service that touches just enough of the original work to entertain you.
Well moving on to the sound.
The voice acting, is fairly decent. It would've been so much better if they had Japanese voice acting option, but considering what I see in this game, that probably would've been impossible. I don't think UMD is capable of holding that much information. Voice acting is far from top notch, but it is above average.
The music is really where it hurts. Original Final Fantasy VII was criticized of having poor sound track, but listening to new sound track added into Crisis Core makes you really appreciate how good the sound tracks were in original Final Fantasy VII. The old sound track from original is back, but only about 1/3 of the time. Rest of the time, there are new sound track made for this game and that's just horrible. It is very repetitive and feels very out of place compared to the original music. You can't help but to feel it would've been much better if they just reused all the sound track from original game instead of trying to come up with something new.
As for gameplay, the gameplay is actually quite competent. It's kind of like ATB battle system, but instead of having active time bar you need to wait, you just keep selecting from menu. Add the fact you can move around, this makes the battle feels like semi-action and semi-turn-based. It's a battle system that can semi please both RPG fans and mindless button mashers.
The best part would be the use of materia. The materias are back and it levels up as well somewhat like in the original game. Interestingly, it's not only magic materias that are back. The combination and leveling of materias makes what could be one long button mashing game into fairly interesting game as it allows you to try different methods in battle. Of course you can always just pound X and occasional Square button to beat the entire game, but then again, what game isn't?
And then there is this weird slot machine thing that's called DMZ?, DBZ?, DMC?, DMA? or whatever it's called and this is interesting mix in fairly chaotic battles.
it's a slot machine that keeps going as you fight. It doesn't seem like you have much control over it, but depending on numbers you get on this slot machine gives you enhancement during the battle such as no mp cost, etc.
Also this is how you level up and level your materias. Getting 2 numbers matched means materias level up, and getting 777 means your character levels up. I know it sounds extremely weird, but it somehow works. completely random but it paces itself fairly well and your character seems to level at a pace where it doesn't hinder you or gives you unfair advantage.
The exploration aspect of the game is rather limited. The towns are fairly small with limited indoors you can visit. and actual hostile areas are fairly straightforward. Also with hostile environment and safe exploration phase seems to keep switching places like a tag team wrestling, you tends to get the feeling of going level by level instead of free roaming experience. It is rather difficult to call Crisis Core RPG. I'd say it is more like adventure game than a RPG. Or better yet, interactive movie.
Overall, Crisis Core is what it is. Fan service. It does some admirable job of trying to connect Advent Children and Final Fantasy VII more smoothly, and actually does fairly good job at it, if it wasn't for repulsively corny dialogue, but then again that repulsively corny dialogue IS Advent Children, so I guess that was unavoidable.
Luckily Crisis Core is more friendly towards to the faithful fans that is fond of memories of original FFVII game, meaing to the fans that loved FFVII but hated the bastard children of FFVII, Crisis Core will be more acceptable bastard child of FFVII. To the blind fan boys that gets orgasm to anything called Final Fantasy, this is portable way to get your share of orgasm.