There are two different modes that you can play in
Dynasty Warriors: Gundam Reborn. Each one gives you a different way to look at the game and its objectives. From the Main Menu, you can choose between Official Mode and Ultimate Mode for different ways to play. In Official Mode, you choose which Gundam story you want to play through. You can choose between: Mobile Suit Gundam, Mobile Suit Gundam Zeta, Mobile Suit Gundam: Char’s Counterattack, Mobile Suit Gundam Unicorn, Mobile Suit Gundam Seed, and Mobile Suit Gundam Seed Destiny. Each one of these has its own storyline and plot. You do not have to play them in order, but I would recommend that you start with Mobile Suit Gundam if you’ve never played before, simply because it gives you instructions on how to play and the others don’t. As I mentioned, I haven’t seen the anime, so I was a bit lost on the storylines, but luckily I had a friend over who is a huge fan of the series so he kept me informed as to what was going on. The first player in Official Mode always plays as the character that the game chooses for you. Sometimes it will even change your character in the middle of a battle, to fit the story. The second player can choose their character and Gundam Suit.
The beauty of having someone else over is that you can play two players locally. It splits the screen side by side with the first player on the left rather than top and bottom like Dynasty Warriors. This took some getting used to at first, but since you will be flying your Gundam up and down at times, it makes a lot more sense to split the screen down the middle. On a large wide-screen TV, you’ve got plenty of room to see what you’re doing on your side.
Ultimate Mode is the other place that you can choose to play. Inside Ultimate Mode, you are given shorter scenarios with specific goals rather than a half hour or more mission like some of the Official Mode levels. You can choose any of the characters you have unlocked to play as and any of the suits that they can pilot. You can get a bronze, silver, or gold on each scenario, if you accomplish goals that they want. You’ll only have one "operation" unlocked when you first start (plus three DLC ones if you have purchased those), but once you beat that first one, you’ll unlock more to play.
You can also choose Database from the Main Menu. Database isn’t a mode of play, but it is a collection where you can see everything that you have unlocked during your play time. For each level that you beat you will unlock new Gundam Suits, characters, suit plans, and more. It’s quite nice to have it all in one place so you can keep track of what you’ve gotten from each story.