A good game for all Gundam fans.
Overall the gameplay is identicle to "Mobile Suit Gundam: Federation vs. Zeon Delux" and if you've played that PS2 game then you should have no problem getting into Gundam vs. Zeta Gundam.
This game follows the story of part of the One Year War but mostly follows the story of the "Mobile Suit Zeta Gundam" series. You'll find all the major characters in this game and a huge selection of mobile suits to choose from. No, you can't create your own "character" for this game like you could for Federation vs. Zeon, you'll be playing all the characters from Zeta and a number from "Mobile Suit Gundam" such as Hayato, Kai, Amuro, Rambal Ral, Garma Zabi, ect.
The biggest problem with this game is how repititive it gets. There are more missions then I can count, and I still haven't completed them all. Heck, I've had this game for probably over a year now and I'm at around 300-400 completed missions... and I'm still not done with them all. This means that many of the missions are pretty much the same; they're generic. Of course some missions *are* the same because you'll be replaying them on different characters.
An interesting twist that's in the game is that, while it directly follows the storyline of Mobile Suit Gundam and Zeta Gundam, you can unlock other paths that can affect the ending. Such is... what if Char Aznable wouldn't have betrayed Garma Zabi? What if Amuro Ray joined the Titans? What if Ramba Ral and the Black Tri-Stars survived the One Year War? There are many "what if" missions in this game, which makes it slightly more interesting.
Overall the game is fun and should keep players entertained for quite awhile.