I've finally gotten my hands on a copy of FFIV for the DS, and it was well worth the wait. Excellent graphics and sound; a great, in-depth, and emotional storyline; and a well developed cast make this one of the greatest Final Fantasy games ever made.
Final Fantasy IV was first released on the Super Nintendo, as Final Fantasy II. Since SquareSoft (as they were then known) brought the original Final Fantasy to North America towards the end of the NES' life, they skipped the other 2 FF games on that system (the original FFII and FFIII) and released FFIV on the SNES as FFII in North America. This has since been fixed, with the original FFII getting remakes on the Playstation, Game Boy Advance, and the PSP; and FFIII has also been remade for the DS.
Now for the story. The main character in FFIV is Cecil Harvey, a Dark Knight, who leads the Red Wings, an elite fighting force belonging to the nation of Baron. Lately, the king of Baron has been acting strange, ordering Cecil to attack a harmless village of mages to obtain a Crystal. Cecil does this without hesitation, but after carrying out his orders, he begins to doubt the king and suspects that something strange is going on. Once the king hears of this, he sends Cecil and his friend, Kain Highwind, to a small village to deliver a package. Once they arrive at the village, the package summons a group of monsters, who then proceed to destroy the village. Realizing the pain he has caused, Cecil vows to put an end to the king's nefarious deeds.
FFIV was the first FF game to incorporate the ATB, or Active Time Battle system. It is named so because everything happens in real time; even while you are choosing menu commands, or casting spells or such, the monsters won't hesitate to attack you. This makes the battles progress a lot faster, and a lot more hectic. However, combined with the fact that your party can consist of up to 5 people at once, this also makes the battles much harder. Controlling 5 characters at once while the enemies are constantly attacking you can take a bit of time to get used to. For better or worse though, you do get an overpowered mage early on in the game. This is sort of a double-edged sword; while you do get access to a lot of the more powerful spells early on (such as Meteor), it is hard to efficiently organize such a huge spell list. You'll constantly be thinking "Should I bomb those enemies with Meteor, or should I cast Protect on my party so the fighters and the other mages can last longer? Or maybe I should..." It really does get extremely hectic at times, and when every second counts in a battle, it just makes the game that much harder.
On top of that, the game puts a much stronger emphasis on equipment. For example, one dungeon renders all metallic weapons and armors obsolete, changing their attack/defence points to zero. So, you must fly around from town to town looking for non-metallic weapons and armors for your party to equip. This is pretty easy for mages, since they usually use wooden sticks and robes, but you'll have to do a bit of grinding and drop hunting to find non-metallic swords, or spears, or such.
Another small complaint I have with this game is how frequently your party changes. With such a huge cast, party members constantly come and go. For example, at the beginning of the game, you are in control of Cecil and his friend, Kain. After a while, Kain leaves, taking all of his equipment with him, and a new character, Rydia, comes into your party. Then Tellah the mage joins. Then Edward the bard, and Yang the monk. Then Tellah suddenly runs away, and Rosa, a white mage, joins you. Then all of a sudden, a huge monster attacks you at sea, and everyone is thrown overboard. While this isn't a huge, glaring flaw, it does get kind of annoying after a while. Like, you've spent so much time with these characters; leveling them, getting them awesome equipment, and then they just leave. In a way, these (somewhat) emotional moments do contribute to the story, and it occasionally helps flesh out the characters.
Now for the changes. The most obvious one are the graphics; they are now in full 3D, and I think the graphics in FFIV are a little better than the graphics in FFIII. The character models have more detail, and the general design of the characters are greatly improved. FFIV also sports voiced cut scenes using the ingame character models. In addition, the opening FMV looks amazing, even better than the one in FFIII. Pretty much the only gripe I have are some of the voices. For the most part, all the voice actors did an excellent job delivering their lines, but some of the voices themselves sound a little silly. One example would be Tellah's voice. In the game, Tellah is an old, somewhat kooky, mage. His voice actor chose to use a stereotypical "mad scientist" voice, full of fluctuations and cracks. While this does somewhat go with his character, it is still pretty annoying to hear him speak, and it is very out of place with the rest of the characters, who usually speak in more somber voices. Kain Highwind sounds like sort of like the Batman in the newer movies (Batman Begins and The Dark Knight); his voice is really deep and raspy. For better or worse though, these voiced cutscenes don't occur that often; usually only after major plot developments. The music sounds excellent; FFIV does have a pretty stellar soundtrack, even when compared to some of the other FF games, and being on the DS only helps it sound that much better.
As for maturity, this is definately not a child's Final Fantasy. It deals with some pretty heavy themes, like betrayal, death, love, and redemption. Because of that, I would only suggest it to players over 15. But even if you did give it to a younger player, they probably wouldn't enjoy it as much as some of the other FF games because of it's high difficulty.
In conclusion, FFIV is a great RPG, and I personally think it stands toe-to-toe with FFVI, which is arguably the best FF game ever made in my opinion. The excellent story, characters, and gameplay definately make this a must own, at only $40. While the difficulty does take a bit of time to get used to, you are in for an extremely rewarding experience if you stick to it all the way to the end.
+Large, interesting cast of characters
+Plenty of bonus features and extras to do after you complete the main game
+Voiced cut scenes
-Slightly cheesy voice acting (specifically Tellah)