Dragon Ball Z games have run the quality gamut from terrible to very good. Infinite World lands somewhere in between. There are only three main modes in Infinite World: Dragon Mission, Dragon Duel, and Fighter's Road. Dragon Mission is the game's story mode, taking you through the Z and Dragon Ball GT sagas in a condensing of hundreds of DBZ episodes. This amalgam covers all of the major battles including, those versus Vegeta, Frieza, Cell, Buu, and more.
You guide Goku along an overwold map in order to trigger battles and minigames. You're also free to replay earlier battles as an easy way to build up your bank account. Extra Zeni (money) can be used to purchase upgrades for you character in the Warrior's Room shop. Short animated cutscenes from the anime play before and after every boss confrontation and give you an indication of what's going on in the story, but they won't make a great deal of sense if you've never watched the show. The bosses get increasingly difficult as you progress through the story mode, but for the most part they play similarly, and your strategy for taking down two different bosses like Vegeta or Frieza won't differ very much.
A smattering of minigames allow you to experience cherished scenes from the anime such as guiding Goku along Snake Way, capturing Bubbles the monkey, and other memorable moments that don't involve outright combat. Unfortunately, these side minigames are poorly designed and overly simplistic. The mission on Snake Way, for instance, has you running along the winding path moving from checkpoint to checkpoint. Another minigame has you training Goku in your space capsule by hitting a series of button combinations. It may be nice fan service, but these minigames really only serve to bring the combat to a grinding halt without being entertaining enough to justify the interruption.
Dragon Duel is the two-player versus mode in Infinite World. You can fight a friend or computer opponent with any of the game's more than 40 warriors. You have the option of playing as any of the fighters, either without their more powerful skills and attacks or with customized power-ups you can purchase from the Warrior's Room shop. Fighter's Road is a secret mode you can unlock after playing Dragon Mission, pitting you against more than 100 opponents across four maps. It's similar to Dragon Mission mode in that you guide a character from fight to fight on an overworld map, but it also provides you with an opportunity to unlock new warriors and earn more Zeni.
Even at the budget price, you would be better off skipping Infinite World for an older DBZ entry such as Budokai 3.
Despite the prevalence of minigames in Dragon Mission mode, Infinite World is still all about the combat. You fly around a battlefield with your opponent and exchange a variety of Ki beam blasts, grapples, and melee combos. You have a healthy variety of attacks, a Ki Burn ability that gives you increased speed and strength for a short period of time in exchange for Ki energy, and the ability to transform into a Super Saiyan. You can speed burst around the battlefield, but you'll have to use it wisely and avoid taking too many hits since they contribute to a fatigue meter. Once the fatigue meter reaches full capacity, it will temporarily stun you, leaving you defenseless against devastating combos and also downgrading you from an advanced form like Super Saiyan back to your default form. Overall, though, the battles are fast paced, the AI is relentless, and winning takes quite a bit of skill and strategy since not effectively evading attacks, Ki charging, or Ki burning will result in an easy defeat.