(Note: This is my first review, so bear with me.)
(Extra note: While I tried to avoid spoilers as best as I could, I can't guarantee this review is 100% spoiler-free.)
Why, you ask? Because I felt like it.
Now then, I bought Sonic Heroes for the Gamecube after playing the demo on my brother's Xbox. The game follows four teams of three characters each, all from the Sonic universe, as they all follow their own storyline in dealing with the evil Doctor Eggman. Now let me just get the big shameful confession out of the way and get it over with:
I had never played a Sonic Game until this one.
Some people might say this disqualifies me from reviewing this one, but I don't think that applies. Being new to the series will at least ensure that I'm not affected by nostalgia, and judge the game by it's own merits, rather than compare it to old titles. With that in mind, let's get right into it.
Writing:
Kindly note I didn't say "story", since a game can still have nice writing even if the story is virtually non-existent (Serious Sam, for instance).
The motivations for each team are all simplistic like nobody's bussiness, and most of the dialogue lies somewhere between "irrelevant" and "terrible", with many of the game's futile attempts at humor being so atrocious that it makes Comedy Central look like fucking Shakespeare.
Now of course, people don't buy Sonic games for epic story-telling but I do honestly feel that the script for Heroes is one of the most dry and uninspired I've ever seen. The plot-twist at the end, in particular, can be seen from fucking Jupiter and is about as smooth and natural as a rusty chainsaw lodged in a hobo's cranium.
I'd like to know what type of rock erodes into a perfect chessboard-pattern.
Graphics:
While hardly the most dazzling game of all time, the enemies and levels are all colourful and varied, and it's usually fairly easy to tell where you're going. The designers went with practicallity rather than beauty, and they made, to my mind, the right call. I must confess however, that the levels (partly due to their length, partly due to the many, many deaths you'll have, see further down) get a bit repetitive and bland after a while. There's about 7 or so major area's, each with usually three levels in them. And by the time you're halfway through the second level, you're begging for some variety. And while new enemies get introduced in later levels, many of them are just tougher versions of old ones with a new paint-job. In all seriousness though, there's essenially nothing wrong with the game's looks and the graphics are probably the only part of the game that I can call "good" without having to add massive amounts of fine print.
Sound:
I'm torn on this one.
On one hand, most of the game's soundtrack is the kind of fast-paced music that's needed for a Sonic game and overal it's pretty good at setting the mood. I also found that a few of the tracks were actually also rather enjoyable as a work on their own, and all in all the music is about 95% fine, with just the remainder 5% being atrocious upbeat, kiddy pop-tunes.
But then there's the voice-acting.
I actually went to IMDB to see who they got to do the voice-acting so I could make a Kill Bill-style hit-list (William Corkery, you're a dead man).
Save for Baten Kaitos, this game has the single worst cast of voice-actors I've ever heard. Tails and Cream in particular made me want to fuck my own ears with a screwdriver, just to make sure I'd never hear something this bad ever again. And when you combine a terrible script with abysmal actors, you get torture worthy of Guantanamo Bay. Apart from that, most of the sound-effects are pretty good, though it'll be hard to notice them what with Tails breaking in every five seconds to violate your eardrums.
"Guys, when exactly did we begin to suck so badly?"
Gameplay:
And now for the big one.
Gameplay is what makes or breaks a Sonic game and upon completing Sonic Heroes I came to the conclusion that it managed a little bit of column A and metric fuckton of column B. You see, the most important thing you have to understand if you want to enjoy Sonic Heroes is that you do things it's way, not yours. The levels are almost prefectly linear, which is par for the course in a Sonic game, but it not only do you have to follow one specific route, you have to follow it in one specific way as well.
For the uninitiated, let me quickly describe the gameplay so you understand just how infuriating this really is.
All of the four teams have three members, each belonging to one of three types: Speed, Power and Flight.
You basically run your ass from one end of the level to the other, all the while running through loops, grinding on rails, being launched by springs, riding trolleys, being fired out of cannons and using the special abilities of your team-members team-members to advance. But there is some difference between the teams. Team Sonic is pretty much what I described above, whereas Team Rose is toned-down piss-easy version of Team Sonic, and Team Dark is an almost harrowing über-version of the aforementioned. The odd one out in all of this, is Team Chaotix (see their private section further down). Anyway, you might think that with different types of characters and so many gameplay-mechanics, each level has multiple routes and many hidden secrets that reward exploration.
To be brief: NO, IT FUCKING DOESN'T.
While it is true that each level features one or two forks in the road from which you can choose to go on following a route dedicated to one of your three characters, these are essentially side-tracks on what is otherwise a single straight road. To clarify: Say that I'm running through a level, and when I'm at the 40%-point, I get to go to the 60%-point by taking the Speed-route, the Power-route or the Flight-route. This might sound reasonable, but it still leaves 80% of the game tied down to using a particular character at a particular time, which to my mind is missing out on a golden oppurtunity.
It's almost as if Sonic Team built a big-ass wall, and then gives us the choice of which ladder we use to get over it. We never get to around the wall, under the wall, through the wall, or even so much as look around and see what else is there besides the motherfucking wall. And while it might be very nice wall, and while we might have a grand selection of ladders at our disposal, it doesn't change to fact that ladders and walls can only hold one's attention for so long.
Like I said, it might not be pretty, but at least you can tell what the fuck's going on.
But before I explain how the gameplay is not only limited but also highly flawed (thereby proclaiming the last death-sentence this game needs), I would like to point out Sonic Heroes' one saving grace:
There might only be one route to get across the level, and there might only be one way to traverse that route, but I must admitt that if you can actually nail that route and find out how to traverse it, then Sonic Heroes is actually fun. Yeah, that's right. Fun. If you play it the way the creators intended, then it's a high-speed platformer with challenging gameplay and a great sense of personal connection. It really does make you feel like it's actually you that shooting through those loops, grinding across that airship or escaping that giant alligator. But of course, it's exactly at moments like that, that the giant flaws in the gameplay become apparent.
Let's just go right to the big one, the one that made my brain want to digest itself in frustation: The falls.
About 99% of all surfaces you can stand on, are devoid of railing, ridges or anything to prevent you from falling to instant death. So, say I'm using Sonic's homing attack against one of Eggman's robots, then when I've killed it and want to use it against the next one, the game hasn't had time to adjust the god-awful camera yet, so instead of Sonic's homing attack smashing him into my enemy, it sends him flying over the edge, which brings back memories of Tomb Raider and good old Jagged Rock Junction. Also, here's another scenario you're likely as not to encounter sooner or later: You just finished grinding down a rail at high speed, you land on the ground, and because you didn't adjust your speed the very instant you landed, you maintain that high speed you had on the rail and thus instantly shoot over the edge, and plummet towards your bloody death. Or say an enemy manages to hit me. This is annoying enough as is without also being close to an edge, in which case even just brushing up against the weakest enemy in the entire game can result in an instant death. And because Sonic Team doesn't understand yet that they're not making arcade-games anymore, Sonic Heroes still works with that fucking lives-system. Lose all of them (and this will happen more often than not) and you have to start the entire fucking level all over again. Combine this with a shitty camera, sloppy controlls and that cunting rings-system, and you've got one of the most frustating forms of gameplay of all time.
Team Chaotix:
Unlike the other three teams, who really do pretty much nothing except run from point A to point B, Team Chaotix has a distinct mission-based style of game-play, where at the end of each of level there's a warp back to the starting-point so you can revisit places that you missed until you finally complete the level's objective. This turns their campaign into an almost sandbox-like experience, which when compared to fast-paced platforming of the other teams is rather jarring. The problem is that the missions are all basically scavenger hunts. Okay, so sometimes you have to collect a bunch of hermit-crabs, and sometimes you have to kill every enemy in the level and sometime you have extinguish all the torches but eventually it all boils down to "go to point X and push button Y to achieve objective Z", which gets really boring really fast and means you have to search every corner of every level at least three times before you're done.
Play Time/Replay Value:
Once you've completed the four main storylines, you can unlock the last one by gathering the seven Chaos Emeralds, which I guarantee you'll be spending a few hours on, so the game will keep you at it for a while at least. Also there's some super-secret hidden feature that you can only get if you get an A-rating on every mission but that's only for the people who can get 100% on Dragonforce in Guitar Hero or can beat Metroid Prime in 2 hours. The multiplayer-mode is a fucking joke, and not even worth discussing.
Conclusion:
By now it should be obvious that Sonic Heroes is a flawed game at best and a large turd at worst, but in writing this review I find myself reminded of Yahtzee's review of Alone In The Dark. I genuinely believe that Sonic Heroes could have worked, if they had seriously tightened up the gameplay and gotten some halfway-decent voice-actors and writers. There was actually potential here for a truly great 3-D Sonic game, as evidenced by the occasional moments of true awesomeness and fun, but it's just too little, too late. All in all, the game definetly has a couple of strong points but there is just so much shit to go with it that I ultimately have to let it go.
Just do yourself a favour, and don't buy Sonic Heroes.
(Extra note: While I tried to avoid spoilers as best as I could, I can't guarantee this review is 100% spoiler-free.)

The twelve main characters: On the right, Team Dark (Omega, Rouge and Shadow). In the middle (top): Team Rose (Cream, Big and Amy).
In the middle (bottom): Team Sonic (Tails, Sonic and Knuckles). And on the right, Team Chaotix (Vector, Espio and Charmy).
Yes, I am actually reviewing Sonic Heroes.In the middle (bottom): Team Sonic (Tails, Sonic and Knuckles). And on the right, Team Chaotix (Vector, Espio and Charmy).
Why, you ask? Because I felt like it.
Now then, I bought Sonic Heroes for the Gamecube after playing the demo on my brother's Xbox. The game follows four teams of three characters each, all from the Sonic universe, as they all follow their own storyline in dealing with the evil Doctor Eggman. Now let me just get the big shameful confession out of the way and get it over with:
I had never played a Sonic Game until this one.
Some people might say this disqualifies me from reviewing this one, but I don't think that applies. Being new to the series will at least ensure that I'm not affected by nostalgia, and judge the game by it's own merits, rather than compare it to old titles. With that in mind, let's get right into it.
Writing:
Kindly note I didn't say "story", since a game can still have nice writing even if the story is virtually non-existent (Serious Sam, for instance).
The motivations for each team are all simplistic like nobody's bussiness, and most of the dialogue lies somewhere between "irrelevant" and "terrible", with many of the game's futile attempts at humor being so atrocious that it makes Comedy Central look like fucking Shakespeare.
Now of course, people don't buy Sonic games for epic story-telling but I do honestly feel that the script for Heroes is one of the most dry and uninspired I've ever seen. The plot-twist at the end, in particular, can be seen from fucking Jupiter and is about as smooth and natural as a rusty chainsaw lodged in a hobo's cranium.

I'd like to know what type of rock erodes into a perfect chessboard-pattern.
Graphics:
While hardly the most dazzling game of all time, the enemies and levels are all colourful and varied, and it's usually fairly easy to tell where you're going. The designers went with practicallity rather than beauty, and they made, to my mind, the right call. I must confess however, that the levels (partly due to their length, partly due to the many, many deaths you'll have, see further down) get a bit repetitive and bland after a while. There's about 7 or so major area's, each with usually three levels in them. And by the time you're halfway through the second level, you're begging for some variety. And while new enemies get introduced in later levels, many of them are just tougher versions of old ones with a new paint-job. In all seriousness though, there's essenially nothing wrong with the game's looks and the graphics are probably the only part of the game that I can call "good" without having to add massive amounts of fine print.
Sound:
I'm torn on this one.
On one hand, most of the game's soundtrack is the kind of fast-paced music that's needed for a Sonic game and overal it's pretty good at setting the mood. I also found that a few of the tracks were actually also rather enjoyable as a work on their own, and all in all the music is about 95% fine, with just the remainder 5% being atrocious upbeat, kiddy pop-tunes.
But then there's the voice-acting.
I actually went to IMDB to see who they got to do the voice-acting so I could make a Kill Bill-style hit-list (William Corkery, you're a dead man).
Save for Baten Kaitos, this game has the single worst cast of voice-actors I've ever heard. Tails and Cream in particular made me want to fuck my own ears with a screwdriver, just to make sure I'd never hear something this bad ever again. And when you combine a terrible script with abysmal actors, you get torture worthy of Guantanamo Bay. Apart from that, most of the sound-effects are pretty good, though it'll be hard to notice them what with Tails breaking in every five seconds to violate your eardrums.

"Guys, when exactly did we begin to suck so badly?"
Gameplay:
And now for the big one.
Gameplay is what makes or breaks a Sonic game and upon completing Sonic Heroes I came to the conclusion that it managed a little bit of column A and metric fuckton of column B. You see, the most important thing you have to understand if you want to enjoy Sonic Heroes is that you do things it's way, not yours. The levels are almost prefectly linear, which is par for the course in a Sonic game, but it not only do you have to follow one specific route, you have to follow it in one specific way as well.
For the uninitiated, let me quickly describe the gameplay so you understand just how infuriating this really is.
All of the four teams have three members, each belonging to one of three types: Speed, Power and Flight.
You basically run your ass from one end of the level to the other, all the while running through loops, grinding on rails, being launched by springs, riding trolleys, being fired out of cannons and using the special abilities of your team-members team-members to advance. But there is some difference between the teams. Team Sonic is pretty much what I described above, whereas Team Rose is toned-down piss-easy version of Team Sonic, and Team Dark is an almost harrowing über-version of the aforementioned. The odd one out in all of this, is Team Chaotix (see their private section further down). Anyway, you might think that with different types of characters and so many gameplay-mechanics, each level has multiple routes and many hidden secrets that reward exploration.
To be brief: NO, IT FUCKING DOESN'T.
While it is true that each level features one or two forks in the road from which you can choose to go on following a route dedicated to one of your three characters, these are essentially side-tracks on what is otherwise a single straight road. To clarify: Say that I'm running through a level, and when I'm at the 40%-point, I get to go to the 60%-point by taking the Speed-route, the Power-route or the Flight-route. This might sound reasonable, but it still leaves 80% of the game tied down to using a particular character at a particular time, which to my mind is missing out on a golden oppurtunity.
It's almost as if Sonic Team built a big-ass wall, and then gives us the choice of which ladder we use to get over it. We never get to around the wall, under the wall, through the wall, or even so much as look around and see what else is there besides the motherfucking wall. And while it might be very nice wall, and while we might have a grand selection of ladders at our disposal, it doesn't change to fact that ladders and walls can only hold one's attention for so long.

Like I said, it might not be pretty, but at least you can tell what the fuck's going on.
But before I explain how the gameplay is not only limited but also highly flawed (thereby proclaiming the last death-sentence this game needs), I would like to point out Sonic Heroes' one saving grace:
There might only be one route to get across the level, and there might only be one way to traverse that route, but I must admitt that if you can actually nail that route and find out how to traverse it, then Sonic Heroes is actually fun. Yeah, that's right. Fun. If you play it the way the creators intended, then it's a high-speed platformer with challenging gameplay and a great sense of personal connection. It really does make you feel like it's actually you that shooting through those loops, grinding across that airship or escaping that giant alligator. But of course, it's exactly at moments like that, that the giant flaws in the gameplay become apparent.
Let's just go right to the big one, the one that made my brain want to digest itself in frustation: The falls.
About 99% of all surfaces you can stand on, are devoid of railing, ridges or anything to prevent you from falling to instant death. So, say I'm using Sonic's homing attack against one of Eggman's robots, then when I've killed it and want to use it against the next one, the game hasn't had time to adjust the god-awful camera yet, so instead of Sonic's homing attack smashing him into my enemy, it sends him flying over the edge, which brings back memories of Tomb Raider and good old Jagged Rock Junction. Also, here's another scenario you're likely as not to encounter sooner or later: You just finished grinding down a rail at high speed, you land on the ground, and because you didn't adjust your speed the very instant you landed, you maintain that high speed you had on the rail and thus instantly shoot over the edge, and plummet towards your bloody death. Or say an enemy manages to hit me. This is annoying enough as is without also being close to an edge, in which case even just brushing up against the weakest enemy in the entire game can result in an instant death. And because Sonic Team doesn't understand yet that they're not making arcade-games anymore, Sonic Heroes still works with that fucking lives-system. Lose all of them (and this will happen more often than not) and you have to start the entire fucking level all over again. Combine this with a shitty camera, sloppy controlls and that cunting rings-system, and you've got one of the most frustating forms of gameplay of all time.
Team Chaotix:
Unlike the other three teams, who really do pretty much nothing except run from point A to point B, Team Chaotix has a distinct mission-based style of game-play, where at the end of each of level there's a warp back to the starting-point so you can revisit places that you missed until you finally complete the level's objective. This turns their campaign into an almost sandbox-like experience, which when compared to fast-paced platforming of the other teams is rather jarring. The problem is that the missions are all basically scavenger hunts. Okay, so sometimes you have to collect a bunch of hermit-crabs, and sometimes you have to kill every enemy in the level and sometime you have extinguish all the torches but eventually it all boils down to "go to point X and push button Y to achieve objective Z", which gets really boring really fast and means you have to search every corner of every level at least three times before you're done.
Play Time/Replay Value:
Once you've completed the four main storylines, you can unlock the last one by gathering the seven Chaos Emeralds, which I guarantee you'll be spending a few hours on, so the game will keep you at it for a while at least. Also there's some super-secret hidden feature that you can only get if you get an A-rating on every mission but that's only for the people who can get 100% on Dragonforce in Guitar Hero or can beat Metroid Prime in 2 hours. The multiplayer-mode is a fucking joke, and not even worth discussing.
Conclusion:
By now it should be obvious that Sonic Heroes is a flawed game at best and a large turd at worst, but in writing this review I find myself reminded of Yahtzee's review of Alone In The Dark. I genuinely believe that Sonic Heroes could have worked, if they had seriously tightened up the gameplay and gotten some halfway-decent voice-actors and writers. There was actually potential here for a truly great 3-D Sonic game, as evidenced by the occasional moments of true awesomeness and fun, but it's just too little, too late. All in all, the game definetly has a couple of strong points but there is just so much shit to go with it that I ultimately have to let it go.
Just do yourself a favour, and don't buy Sonic Heroes.