This game covers the Dragon Ball Z sagas (or seasons) running from the beginning of the series up through the journey to the planet Namek and the battle with Freiza. The game features nearly all the warriors from the anime, mostly in the battles they were involved in within the series. The game uses a somewhat unique (at least for the time) turn-based card battle system wherein one uses cards with different offensive and defensive values to execute different moves, including several special moves unique to each character. The status of the cards are indicated by the Dragon Balls on the corners of it, the more stars on each, the higher the offensive or defensive values. Rather than have the usual RPG stats of ATK, DEF, INT, etc., the characters have actual power levels or Battle Power (denonced as BP in the game) that increases as they level up. If you're a fan of the series, power levels are the backbone of fights. The game features random encounters, somewhat anachronistically fought against varying colors of saibaimen, even in the very beginning of the game before they were introduced in the series. The game is unique, not only because it's a Dragon Ball Z RPG, but because there are "optional" secret parts to the game, where if you follow the plot of the anime, you'll gain substantial boosts to your power.
Power up Piccolo - After Piccolo is brought back on Namek, go and find Nail. He will be lying on the ground after getting decimated by Frieza. Fuse with him and Piccolo will be at level 48 which is the level cap, although you can still boost his power level temporarily mid-battle by using a King Kai Card or a Guru Card. After fighting beating Freiza's 2nd form he will run away, during this time you can find the two Namek Warriors that helped you earlier in the game (under the assumption that you didn't get them killed) and you will be given a choice whether to allow them to fuse with Piccolo. If you choose yes, Piccolo gains another largte boost in his Battle Power however you will lose Dende and his healing ability. If you choose no, you get to keep Dende.
Unlock the Super Saiyan form and battle Vegeta as a Super Saiyan - In the final battle against Freiza, allow him to kill either Krillin or Chiaou-Tzu then he'll become enraged and transform into the infamous blonde-haired warrior, giving him a massive power level boost and allowing him pretty much dominate Frieza. After you fly away, you will be confronted and challenged by Vegeta and he will transform into a Super Saiyan and you fight him.
Easy Levels for Saiyans - Goku, Gohan, and Vegeta can level up mid-battle if you use an item that completely restores their health while their HP is 5 or lower. You'll see a short cutscene of the character powering up and it will say something along the lines of "Gains a Level". It's a nice touch since according to the anime Saiyans grow stronger after recovering from mortal wounds or near death. Take advantage of this in the beginning with Goku. Grind and gain a few more levels with this method before fighting Raditz. It will make the game a lot easier once Goku arrives on Namek. When using this method with Gohan and Vegeta, take full advantage. Same as with Goku, grind, heal, level. Repeat. It will be a lot more satisfying to just finish random battles just by using only one character from your party once strong enough. Not to mention the rest of your party levels up every 1 or 2 battles so that's always good.