Final Fantasy Adventure is actually not a Final Fantasy title at all. It was released in Japan as Seiken Densetsu: Final Fantasy Gaiden, which makes it the first game of the Mana series. The game's name was changed when it was brought over to North America.
The story begins with the Hero being forced to fight gladiatorial style battles in the Dark Lord's arena. After escaping the arena, the Hero discovers Dark Lord and Julius, his second in command, plotting by the waterfall that blocks the entrance to the Mana Shrine. Hidden within the shrine is the Mana Tree, and with it, the power to take over the world. The Hero is soon discovered and is subsequently thrown down the waterfall by Dark Lord. He survives the fall, and soon after saves a woman from monsters, who turns out to be the last of the Mana family. After this fateful encounter, the Hero embarks on a quest to save the power of Mana, and become a Gemma Knight, defender of the Mana Tree.
The gameplay in Final Fantasy Adventure feels very similar to the original Legend of Zelda, with some RPG elements thrown in to add some depth. The Hero can equip helmets, shields and armor, as well as a variety of weapons which are necessary to complete your quest. Along his journey he will find axes, spears, chains, a sickle and even a morning star, with each type of weapon having its own special attack. Defeating enemies nets EXP points to raise the Hero's level and stats as well as Gold, which can be used to purchase items and equipment in shops, and a night at an Inn. With each level gained, you can choose one of four attributes to strengthen: Power, Stamina, Wisdom and Will. Power is used for attack points, Stamina for defensive power (possibly HP as well, I'm not 100% sure on that one), Wisdom for more MP, and Will affects the speed with which your attack gauge fills up. Your attacks do more damage when the gauge fills up, and once full, you can use your weapon's special ability. As the game progresses, the Hero will come upon spell books which will allow him to cast offensive and curative magic.
The similarities to Legend of Zelda come through the actual playing of the game. The Hero can only move vertically and horizontally, and he can use his shield to block projectiles. However, the shield you have equipped will determine what kinds of projectiles can be blocked. For example, once you upgrade to a stronger shield, it may not block the same projectiles that the previous one did. Generally though, the shields you find and buy along the way are the shields that are the most effective against the enemies you'll face in that area. Another similarity to Legend of Zelda is that the quest requires the Hero to roam an overworld type of landscape, where you can visit towns, and occasionally go through a dungeon area, where more often than not, a boss character will bar your way. There are also some puzzles to solve in the dungeons, but for the most part, they won't tax your brain too heavily.
One of the best features of Final Fantasy Adventure is the save feature. You can save anywhere, anytime. Whether strolling in a forest, or in the middle of a boss battle, you want to save, you can do it. No need to find an Inn or save point, you just press select, then choose the save option. Simple as that, and extremely handy.
The graphics in the game are actually pretty good for a Game Boy title. Granted, you won't see beads of sweat forming on your Hero's tiny brow as he fights off hoards of monsters, but hey, for a Game Boy game, the sprites are done quite well. Some of the bosses look pretty cool, you can easily identify them with their SNES brethren, as well as some of the minions you encounter along the way.
The learning curve in the game is really quite simple. The A button is for an attack with your weapon, B is for the equipped spell or item. The D-pad makes the Hero move around. Select and Start open up two different menus. If you get hit too much you die. If you kill stuff without dying, you get stronger. That, in a nutshell, is what you need to know to survive in this game.
The game doesn't have a ton of replay value, but the fact is, the gameplay is solid enough that you'll end up playing it again at some point. Most likely, you won't be salivating to start a new quest immediately after finishing your first playthrough, but it's one of those games that are just fun to pick up and play every now and then. You can try to use weaker weapons, weaker armor, etc. to finish the game if you're looking for a bit more of a challenge during the next playthrough.
The sound and music in the game are nothing to write home about. The music in the dungeons gets repetitive fast, but the music in the overworld isn't quite as annoying. It has just about as much epic feel as a Game Boy tune can have. The sound effects aren't spectacular either, but they aren't all that bad. The biggest gripe I had with sound effects is when you hit an enemy, the sound isn't very distinct above the music, which can be somewhat of a problem, since an enemy won't receive damage for a moment after being hit. I wasn't always sure which hit connected, but it didn't take away from the gameplay.
All in all, this is a great game for the Game Boy. The gameplay is excellent, and there's a large world to explore. You'll end up scouring almost every corner of the world as well as do some dungeon crawling. This game lays some of the basic ideas that are later used, and perfected in Secret of Mana. If you've played Secret of Mana, chances are you'll recognize a lot of the enemy characters and bosses that you'll encounter along the way. No matter how tiny they are, there's a certain satisfaction to be had from beating up on rabites and shadow zeros. If you can get a hold of this game, play it, you won't regret it one bit.