While there are many things that StarFox: Assault gets spot on, there are many things in this game that fall short.
First, despite what gamespot says, the gameplay itself is rather flawless. Of course, there are always a few things that could've been done differently. Sometimes the levels feel a little unnecessary, but the game is still very fun. (I especially enjoyed kicking my little brother's a$$ in the two player dogfights). I have many memories surrounding this game.
My biggest beef with the game is the rather annoying storyline. I honestly enjoyed the Starfox Adventures storyline--even though it could feel a little clichéd at times. However, Starfox: Assault feels like the developers wrote a script, put it through a shredder and then put it back together in a different order. It's not hard to follow. It's just that it's so poorly written that I feel like it was an afterthought in the game.
I do have a couple issues with level design. There are some that just aren't that fun. However, when you unlock the desert level, you will be in for quite a suprise. Not only is the level huge, but it is probably one of the most fun levels I've played in any multiplayer game.
Lastly is the amount of content in the game. While, at this point, the game is well worth the cheap price tag, at the time of it's release, it wouldn't have been worth buying the game knowing that there are very few levels, characters and modes to play with. It looses it's magic after a month or so of playing (unless you get friends together, no party game could be boring when you got a couple of peeps throwing smack talk around the table).
All in all, the game is good--worth the couple of bucks you would pay to get it for your old Gamecube or Wii system. Buy the game and enjoy it for what it is.