You know, having spent 2 days with it, I think IGN's review was extremely fair. I'm a huge StarFox fan, but this title just doesn't have the pizzazz that the previous two did - especially since the boss battles just lack the inspiration and jaw-dropping coolness of SF64.
Another thing, is that 7/10 levels are the arena-style levels - all of which play exactly the same. They're fun at first, but then you realilze that they really lack depth - not to mention that it is really, really annoying trying to help your mates out when you're on foot.
I'm surprised no one has drawn this comparison, but those arena missions feel a lot like the single-player campaign from Star Wars: Battlefront - you're running around, trying to take out the enemy spawn points, can jump in air and ground vehicles, etc.
I think this is where the multiplayer complaints come in; this game is just *begging* for a cooperative mode, but all it has is deathmatch. With cooperative, this game would have absolutely owned - one guy, running around on the ground or inside, plugging bugs, while the other person circled in an arwing and protected them. Without it.... it feels shallow and repetative, just like SW: Battlefront did in single player.
The on-rails stuff is classic, fun and pretty - but there's only 3 levels of it! It's pretty bad when StarFox Adventures has more classic Starfox gameplay than this one.
The more I play it, the more I just think, "Meh."