Four Swords is one of the best GC games out there.
Four Swords Adventures had a good story, nostalgic graphics, and some of the best gameplay seen on a current gen system. The game disappointed me with the use of chapters, but I got over it. The minigames are fun, and if you have 3 buddies with GBA links, then you should get a ton of replay value out of this. The single player is satisfying enough, but overall one of the best multiplayer games I've ever played. I wish I played more of it though.
----------Battle System----------
Four Swords Adventures is almost a re-imagining of Link to the Past, one of my favorite games of all time. The move set is pretty similar, you can slice, holding the attack and swing attack and so on. If you're playing a single player mission you can control all 4 Links at once. This makes for an interesting puzzle game. now you aren't arguing with friends over how to do a puzzle or which way to go, you have to figure it out for yourself. You can set Link in 4 formations, a straight line going up, a straight line going left to right, a block or a cross format. All of these formations will match any puzzle you'll encounter in a 4 player game. Some puzzles involving going solo, so all you have to do is hit the X button and the other 3 Links will pause, you can maybe lift up another Link and throw him over somewhere, or anything other useful way to use them.
Through out the game you'll find various weapons for example, a boomerang, jump feather, etc. If you're playing a single player game, you can only hold one item at a time. When you switch items, the item you held last will drop where you left it and it won't disappear. If you need it again you'll have to backtrack to it, but it's only a minor inconvenience. In a four player game everyone can hold 1 weapon each, this makes the game move a bit smoother.
Collecting Force Gems is pretty useful in the game. If you collect over 2,000 Force Gems you get an extra move and you can shoot beams out of your sword. Sometimes Tingle will come out of no where to try and still your gems. In a four player game the main objective is to get the most Force Gems before the end of the stage. After each stage is over you get to answer questions about the other 3 players with your GBA, I can't remember exactly what happens. I think the person with the most gems wins bragging rights, but it was pretty fun stuff.
There's some pretty fun multiplayer VS action on this as well. The GBA is a great multiplayer tool for these type of games. For an example, you can hide in a cave and get ready to pounce on someone, and they wouldn't be the wiser.
----------Characters / Story----------
The story sets you up by Zelda telling Link about the Wind god Vaati, as they're trying to seal him, he captures Zelda and the 6 Maidens. As Link goes to get the sword, he splits into 4 Links. Link must save all the Maidens and Zelda, get rid of the pesky Shadow Link and kill Vaati to save Hyrule. You find alot of people on the way, including the Owl from Link's Awakening and Ocarina of Time, Malon & Talon, Tingle and a few other familar faces. This was a pretty good story (although a bit similar to Link to the Past).
----------Graphics----------
For the style it's going for, the graphics are awesome and a true testament that you don't breathtaking realistic graphics to have fun. The camera is really good in this game at keeping all the characters on screen at once. If everyone is spread out across the screen, then the camera will zoom out as much as possible to keep everyone on. If you're playing single player, then the GBA screen will pop up, the graphics on this are pretty weak, but these screens are short, so it doesn't matter. If you use a GBA, you can see these on your GBA screen instead.
----------Sound----------
The music is a great nostalgia flashback. Everyone is familiar from the classic Zelda titles, especially most of it comes from Link to the Last. There's no voice overs, but Tingle will say a couple links and Link will grunt, that's about it.
----------World Map----------
The World map is very similar to the one from Link to the Past buuuut it's not a free roaming map. Four Swords Adventures is actually a chapter to chapter based game. I was a bit disappointed in that, but it grow on me and it really works well. There's 8 chapters overall with 3 levels to each Chapter. The levels have a good amount of length to them, but they're pretty linear overall.
----------Time to Complete Game (first run through)----------
9:43:57
You can continue playing after you finish the game, and try to unlock any Tingle minigames you missed during the first run through. I wish the game was a bit longer though.