Alternate costumes - Successfully complete the game. Then, highlight one of the following characters at the character selection screen and hold Triangle until their name turns yellow.

Frieza
Gohan
Krillin
Trunks
Vegeta

Bonus difficulties - Successfully complete the indicated task to unlock the corresponding difficulty:

Hard: Successfully complete Z Chronicles on the Normal difficulty.
Very Hard: Successfully complete Z Chronicles on the Normal difficulty.
Z: Successfully complete Z Chronicles on the Very Hard difficulty.

Movies - Successfully complete the indicated task to unlock the corresponding movie:

Credits: Successfully complete Broly's Storyline.
Movie 1: Successfully complete Frieza Saga.
Movie 2: Successfully complete Cell Saga.

Control loading screen - Use the Left Analog-stick and Right Analog-stick to roll the Dragon Balls along the ground. Press X and Y to make the Dragon Balls bounce very high. Repeated pressing can result in extreme height on Dragon Ball bounces with the correct timing. Press A and B to get a weaker bounce.

Defeating 100% Final Form Frieza easily - When you are fighting 100% Final Form Frieza in the storyline, if you can get close enough without him attacking you, keep pressing LT + Y. You can keep hitting him without him being able to attack back. If he does get out, you can also keep using Kamehameha.

Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

The Story Begins (5 points): Clear the first chapter of the Saiyan Saga.
Meeting a Rival (5 points): Clear all chapters of the Saiyan Saga.
The First Z Award (20 points): Clear a chapter with a Z rank on Normal difficulty.
Saiyan Z Award (35 points): Clear all Saiyan Saga chapters with a Z rank on Normal difficulty.
Fierce Warrior (40 points): Clear all of the Saga chapters with the difficulty set to Very Hard.
Full Drama Unlock (5 points): Unlock all of the Drama Pieces for one character.
Saiyan Saga Drama (20 points): Unlock all of the Drama Pieces from the Saiyan Saga.
All Saiyan Fighters (5 points): Unlock all of the Saiyan Saga fighters.
Saiyan Saga Allies (5 points): Unlock all of the Saiyan Saga ally characters.
Worldwide Contender (5 points): Join 10 sessions over Xbox LIVE.
Worldwide Warrior (5 points): Create 10 sessions over Xbox LIVE.
Battler (Default) (5 points): Play the Survival Trial (Default Drama).
Speed Beyond Terror (5 points): Clear the Time Attack Trial (Course A) and get a result.
Score Beyond Terror (5 points): Clear the Battle Point Trial (Course A) and get a result.
A Beginner Awakens! (5 points): Clear Basic tutorials.
Bloodless Victory! (20 points): Win a battle without taking any damage. (Z Chronicles/Versus only).
Destructive Win! (5 points): Win a battle while changing or destroying the background. (Z Chronicles/Versus only).
Unleashed Ki Win! (5 points): Transform, use Aura Spark, and win with an Ultimate Attack. (Z Chronicles/Versus only).

Additionally, there are 32 secret achievements:

Advanced Victory! (15 points): Clear Advanced tutorials.
Legendary Warrior (15 points): Clear all chapters of the Frieza Saga.
Ultimate Warrior (15 points): Unlock all characters' Ultimate Attacks.
Survivor (Default) (35 points): Play the Survival Trial (Default Drama) and defeat 50 opponents.
Survivor (Custom) (35 points): Play the Survival Trial (Custom Drama) and defeat 50 opponents.
Frieza Z Award (35 points): Clear all Frieza Saga chapters with a Z rank on Normal difficulty.
Z Warrior (40 points): Clear all of the Saga chapters with the difficulty set to Z.
Birth of a Legend (100 points): Play the Survival Trial (Default Drama) and defeat all opponents.
Goku's Father (20 points): Unlock Bardock.
Legendary Saiyan (20 points): Unlock Broly.
All Drama Pieces (40 points): Unlock all of the Drama Pieces for all characters.
Intermediate Fire! (5 points): Clear Intermediate tutorials.
Ultimate Unlock (5 points): Unlock all of one character's Ultimate Attacks.
Sturdy Warrior (20 points): Unlock all fighters.
Frieza Saga Drama (20 points): Unlock all of the Drama Pieces from the Frieza Saga.
Cell Saga Drama (20 points): Unlock all of the Drama Pieces from the Cell Saga.
All Frieza Fighters (5 points): Unlock all of the Frieza Saga fighters.
Frieza Saga Allies (5 points): Unlock all of the Frieza Saga ally characters.
Master of History (15 points): Clear all chapters.
All Cell Fighters (5 points): Unlock all of the Cell Saga fighters.
Family Bonds (15 points): Clear all chapters of the Cell Saga.
Cell Saga Allies (5 points): Unlock all of the Cell Saga ally characters.
Cell Z Award (35 points): Clear all Cell Saga chapters with a Z rank on Normal difficulty.
Z Master Award (35 points): Clear all chapters with a Z rank on Normal difficulty.
Ultimate Z Fighter (100 points): Clear all of the Saga chapters at difficulty Z, with Z ranks.
Ultimate Survivor (100 points): Play the Survival Trial (Custom Drama) and defeat all opponents.
Battler (Custom) (5 points): Play the Survival Trial (Custom Drama).
Speed Beyond Power (5 points): Clear the Time Attack Trial (Course B) and get a result.
Speed Beyond Rivals (5 points): Clear the Time Attack Trial (Course C) and get a result.
Score Beyond Power (5 points): Clear the Battle Point Trial (Course B) and get a result.
Score Beyond Rivals (5 points): Clear the Battle Point Trial (Course C) and get a result.
Powerful Allies (15 points): Unlock all ally characters.

Bonus characters - Successfully complete the indicated task to unlock the corresponding character:

Android #16: Successfully complete Chapter 8 in the Cell Saga.
Android #17: Successfully complete Chapter 3 in the Cell Saga.
Android #18: Successfully complete Chapter 2 in the Cell Saga.

Bardock: Successfully complete Chapter 1 in Bardock's Storyline.
Broly: Successfully complete Chapter 1 in Broly's Storyline.

Captain Ginyu: Successfully complete Chapter 4 in the Frieza Saga.

Frieza (first form): Successfully complete Chapter 8 in the Frieza Saga.
Frieza (second form): Successfully complete Chapter 9 in the Frieza Saga.
Frieza (third form): Successfully complete Chapter 12 in the Frieza Saga.
Frieza (final form): Successfully complete Chapter 14 in the Frieza Saga.
Frieza (100% final form): Successfully complete Chapter 16 in the Frieza Saga.

Imperfect Cell: Successfully complete Chapter 4 in the Cell Saga.

Kaioken Goku: Successfully complete Chapter 7 in the Saiyan Saga.
Krillen: Successfully complete Chapter 6 in the Sayian Saga.

Nappa: Successfully complete Chapter 5 in the Saiyan Saga.

Perfect Cell: Successfully complete Chapter 12 in the Cell Saga.
Piccolo Fuse with Kami: Successfully complete Chapter 4 in the Cell Saga.
Piccolo Sync with Nail: Successfully complete Chapter 11 in the Frieza Saga.

Raditz: Successfully complete Chapter 1 in the Saiyan Saga.
Recoome: Successfully complete Chapter 1 in the Frieza Saga.

Saibamen: Successfully complete Chapter 3 in the Saiyan Saga.
Semi-Perfect Cell: Successfully complete Chapter 6 in the Cell Saga.
Super Perfect Cell: Successfully complete Chapter 18 in the Cell Saga.
Super Sayian 2 Gohan: Successfully complete Chapter 17 in the Cell Saga.
Super Sayian Gohan: Successfully complete Chapter 16 in the Cell Saga.
Super Saiyan 2 Teen Gohan: Successfully complete Chapter 19 in the Cell Saga.
Super Saiyan Goku: Successfully complete Chapter 16 in the Frieza Saga.
Super Saiyan Trunks: Successfully complete Chapter 7 in the Cell Saga.
Super Saiyan Vegeta: Successfully complete Chapter 2 in the Cell Saga.
Super Trunks: Successfully complete Chapter 13 in the Cell Saga.
Super Vegeta: Successfully complete Chapter 10 in the Cell Saga.

Teen Gohan: Successfully complete Chapter 1 in the Cell Saga.
Tien: Successfully complete Chapter 3 in the Sayian Saga.
Trunks: Successfully complete Chapter 7 in the Cell Saga.

Vegeta: Successfully complete Chapter 8 in the Saiyan Saga.

Yamcha: Successfully complete Chapter 4 in the Sayian Saga.