This game is "truer to it's 2D roots"... I'll tell you why: It suffers from a total lack of Depth.

User Rating: 4.4 | Sonic Heroes GC
Don't prejudge me, I have no grudges. I like almost every Sonic related game out there, especially the older ones; But this is the worst one I have ever tried.

Although it was, to tell you the truth, a bad game, me and my friends have explored the game quite thouroughly(I am (or was?) a Sonic fan). Here I will tell you about all the horrible mistakes they made. Some might not be so noticeable for a baby who has never played Sonic before, but they are very clear to me. I am comparing this to it's predecessors(like Sonic Adventure1&2) and Shadow the Hedgehog.

The gameplay is based on you controlling a group of three characters from previous Sonic games. The 4 groups are premade, and every character has his abilities. This could be interesting, but it is not well executed. All characters of one type are the same(they changed a few variables like their power though), with a few exceptions.
For example, in addition to her normal speed abilities, Amy can actually fly with her hammer. Ridicolous.
Speaking about Amy, "Team Rose"(which is located at space 3 in the group select) is the easiest group to be. Made for newbies, like some sort of tutorial. Being them is plain boring, with their cowardish abilities: Especially if you play with them the third time you play through the game.

The flying mechanics are horrible. You can fly straigt up, and suddenly you stop. You can hang there for a year. Then, you can fly a certain distance ahead. Suddenly you fall straight down and usually die. The game has no physics at all. It's more like an old 2D Mario game in 3D game than a Sonic game. You can run, but every five seconds you either meet an invisible wall, a platform which is just a graphic(meaning you fall right through), an enemy that pops out of nowhere, or a preprogrammed path with constant speed(like a loop). Also the speed limit very low and very sudden. The gameplay is choppy to the bone.

The sound is not good either. First, the music is moodless and repetitive. Most consists of two 3-second riffs that are played in a random order several times, maybe even with some random notes on top of them.
Some of it is a bit more complex, but still not cool in any way. Example: The first level music has nothing to it that would ever make you think that it belongs to a brown and green beach. The theme song is bad pop music.
I must admit, though, that some of the groups' themes(apparently made by someone not directly related to this game) are sometimes interesting.

Second; Sound effects? Nothing new, just edited old ones. That's not too annoying though. It's the way they are used. Everything that moves in the game plays it's own long repeating ugly 8-bit sound, which quickly turns rather annoying.

That was the good part of the sound. Third, the voices, oh, the voices. Every time the smallest thing happens, a voice is played. The voices often have nothing to do with what is happening, they are completely lifeless(it sounds as if they are asked to read a text aloud while sitting in the couch at home), and on top of that, the voice actors themselves have ugly and annoying voices.
Tails(whose voice actor is a young girl(Tails IS a boy)) will make you puke.

A final note: In the GameCube version you cannot adjust the sound/music volume. As default, the music is so low... It creates a twisted mood, very possibly making you sick. If you for some reason own the PC version, either turn the music up or turn it off.

The story is seriously messed up. We learn what has happened bit by bit, which could be cool, but again it is not at all well executed. The truth is that we never learn anything of what we want to know.
Let me retell everything we learn:
Team Sonic gets a letter from Eggman. They trash their plane. Oops we are on a beach. Oops we are in a city. Metal Sonic gathers data from the Heroes wihch he never utilizes. He can also transform into quicksilver. Oops we are on a fleet of airships. Oops we found Eggman. Eggman has made a lot of Shadow clones which he never use. Shadow might be a clone(this is the only interesting part. The game Shadow the Hedgehog is based on this problem). Eggman was locked up all the time and Eggman is Metal Sonic. Metal Sonic mutates into a huge monster. You defeat Metal Sonic. The end.

There are no transtitions between the levels. We get no explanation of how they get there. They had some interesting ideas in the level design but the same few mechanics are used everywhere and nothing feels right. The loops and such are exaggerated and really gives the impression of "trying to be cool but not at all succeeding".

The levels are "true to it's 2D roots" in one way; they more or less lack the third dimension. The roads are thin and you can never choose which way you want to go. There are no shortcuts and nothing to be found. If you step outside the thin road you will either meet an invisible wall or fall straight through the floor. The levels have nothing that even tries to be new. Everything "different" are overused gimmicks.

The graphics are "good" in general criterias. They have lots of polygons and neat lighting effects. But the characters have no textures, very floppy animations, and they look odd(huge heads) compared to the originals. Now this is alright, I'm not that conservative. They look nice if you don't compare them to the old ones.
The real problem with the graphics is that the levels, robots, etc. have:

Little or no detail
Boring, bad, or plain ugly design
No impressive aspects at any point

Eggman seems to have completely lost it in this game. Almost all his robots are, like I mentioned, so ugly anyone above 3 years old with a slight sense of style will rather have them look as black squares on the screen. Also, they are stupid. They just stand there, and eventually they will want to charge you with their spear or hammer. For the flying enemies, who all look the same, they will just hang there and do nothing. Unlike their predecessors' innovative shielding mechanisms that you have to get past, the creators found that they rather wanted: A health bar. All I want to say is O.M.G.
So to beat these enemies, no matter if they are bosses(they are also ugly), ground enemies, flying enemies, strong enemies, you have to press the jump, hit, or launch button repeatedly. Often several hundred times(I mean it!). Of course, some enemies are weak against some attacks, but still: Laughable.

Oh wait! There is one enemy which does not look like a bright-colored blob; It looks like a turtle. To kill it you will actually have to flip it around, and then press the jump button. Impressive!

Do I have something more positive to say?
Yes, one thing is good: They removed the Chao Garden! Also, we don't see many humans.

Gamespot, I think you made a mistake here. This is the kind of game you would usually give a 3.0: Bad. Go to any board with serious, rather intelligent people who play Sonic games, and let them show you the truth.

All in all, only play this game if you have a nostalgic relation to Sonic and his friends, plus you have completed every other Sonic game 100%.