Not underrated, crap is crap.
This game is a train wreck, it gets two stars for the inclusion and look of the characters. The story and dialog are just as horrible as the old cartoons, and while it's funny at first, it just gets sad after the first 10 minutes. It is a huge missed opportunity that could have been a good game. People that like this game are why bad video games are made, some people will buy anything that has a license on it, sight unseen.

The gameplay is sluggish, the controls are horrible, the combat consists of mashing an attack button over and over, and the fact that very few of the characters actually use a gun is stupid. They all run around and punch each other instead of shooting. Soundwave has a wicked flipkick too. The transformation is mostly useless and just for moving from place to place.

This game came out in 2003 people, look at what other games came out then and compare. This game feels like it was made for the N64 and looks it too.

The game could have been a giveaway in the back of a toy and then maybe it could be forgivable, but anyone that spends more than $5 for this game will feel ripped-off.

It's now become something of a myth since many have heard of it, yet few have played it, and it's so bad it's a trip to watch. It looks like something a fan made for YouTube but it actually was a full price retail game in Japan. Like the Star Wars Christmas Special, it's a black spot on the history books that many wish it were to never be seen again.

Avoid at all cost unless you find one for very cheap. It's only "value" is as a novelty.

Transformers = MUST BUY
This Game is great. Purely on the fact it's the only game based on the ORIGINAL TRANSFORMERS series.

however, although i've given the game a 5 star rating. i'm giving an no biased review.

the + points :

-character's from the original series on a PS2 game (who'd of thought it possible)
-the storyline is really well thought out.
-You can change the ENTIRE language of the game, from Japanese to ENGLISH. (Yes you can make the game in full english, the voice acting is already in english, but now all the text is well.) making this game perfect for any engish speaking importer.
-Visually, the game is great. they haven't missed any detail on any of the characters.
-in story mode, you can play the game as either the 'Autobots' or the 'Decepticons' (a really big plus point)
-Combo attacks are a nice touch to the game (the double team combo attacks are cool too.)

the bad points :
-Controls for the game were not well thought out at all. for the most part there fine. but it's the little things like, trying to turn around to fight another enemy, this can take up to a while with you enemy constantly hitting you.
-The Voice acting is... well terrible. (although the voice acting is in english which is brilliant) The casting for the voices was not well thought out at all.
-Another point on the voice acting is the lack of consistency when they’re speaking. (e.g. Jazz says "sure thing" (there a little pause, and then says) "Optimus".) not a major bad point, but you do notice it.

But if you can through the bad points, it's a great, must buy game.
The fact it's going to be the only game on the ORIGINAL TRANSFOMERS series on a next gen console, and more than likely WILL NOT be released outside Japan. i think that's as good as any reason to spend this well priced game.
(from a UK view) £20 is not a bad price for this game at all. well worth it.

Underrated
This game, while not spectacular, is far better than most reviewers have painted it. If you happen to be a fan of the Transformers, that is. The sheer number of characters from the original series makes this worthwhile. Add English text and dubbing, and you're well on your way.

The controls are a little clunky and take getting used to, and, as with any beat-em-up, the levels are a little repetitive, but I managed to overlook those things. The little touches like the Autobot/Decepticon bumpers between cutscenes made the game fun for me. The voice-acting is pretty bad, but it's in English, so I can't complain. If you're looking at this, you're probably a fan of the series, so you'll also probably find this game fun. Buy the cheaper "Best Takara" copy, though.

Transformers Tataki (The Best Takara)
Das ist echt ein HAMMER GAME!!!!!!!!!!!!
Jeder der in den 80-90 zigern jahren die Transformers sich die folgen angesehen hat und so wie ich ein riesen Fan von den alten Transformers sind
und jeder der die neuen ehr schlecht wie recht findet kommt
an diesem spiel nicht vorbei!!!!!
Das spiel hat den flär der alten transformers voll eingefangen!
Es gibt ewig viele Roboter zur auswal und man kann die guten
oder die bösen spielen, ECHT GEIL!!! :-)