Brawl dropped the ball. However, that ball was around the size of a monster truck.
The Local Multiplayer (fighting with and against your friends) works very well in this game, and if you have 2 or more friends around that can play it with you on a regular basis its a must-buy.
On the other hand, Single player isn't too abundant. The game's main one-man attraction is the Subspace Emissary, which can be played with two people, however the two player elements feel very sloppy and being a platformer with two different people, the camera only follows the first player, making you have to magically teleport up to them a lot of the time. Also, just picking up the controller to play with your friend for have a stage is also poor as well, because from what I tried you can't go on through the rest of the level without that second person, unless you wanna save and restart the game. The Subspace Emissary is about 10 hours long and plays very much like the Kirby Franchise and features cameos galore and tells an 'Alright' story. There is no voice acting, but it isn't really needed. The main problem with the Subspace Emissary is that some levels (Especially the last one) can be remarkably painful, and follows the same route of many other fighters: "MUST SURVIVE IN ORDER TO UNLOCK.....CHARACTERS!!!!". After playing through the Subspace Emissary, there's about another 5 or so hours of fun to be had Solo, what with the 41 events and unlockables and such.
After this, however, the game really expires unless you have more people locally. Online play is a MAJOR letdown without friend codes. I am yet to join an Online match, and I must've spent at least an hour in the waiting room.
If you want wacky combat or just Nintendo fan-service and you have other friends you can fight on a regular basis, Brawl is a must-buy, however, would you buy a console just for this? Nope, unless you're one of the people who's clocked in 500+ hours of melee and still somehow has the money to waste.