Battle Stadium D.O.N Unlockables (GameCube)

Battle Stadium D.O.N is a Japanese fighting game for the GameCube and PlayStation 2 featuring characters from the popular anime and manga series Dragon Ball Z, One Piece, and Naruto, hence the D.O.N. This game received a rating of 28/40 from Weekly Famitsu. Unlike other fighting games, D.O.N uses a combined health gauge, that is, decreasing the health of one player will in turn increase the health of the other players. Thus, in order for one player to win a fight, they must make their own health bar take up the entire bar. As such, a fight can potentially last indefinitely if no time limit is set.

The single player mode has the player fight through five rounds, two of which have missions with goals selected randomly. However, depending on the difficulty chosen by the player, different amounts of missions are given out with easy giving the least and very difficult giving out the most. Fulfilling the missions' goals rewards the player with coins that can be used in the slot machine available upon completing the fights.

Unlockables

Characters
Verse the characters in Single Player mode then go into the slot machine and get the Red Flag with the pirate on it to go to the bonus Slot Machine. At the Bonus Machine, get the head with a ? on it to unlock a character. Note: Sometimes the head isn't there and a stage is there instead.

Cell - Vs in Single Player Mode

Frieza - Vs in Single Player Mode

Gaara - Vs in Single Player Mode

Majin Buu - Vs in Single Player Mode

Nami - Vs in Single Player Mode

Rock Lee - Vs in Single Player Mode

Trunks - Vs in Single Player Mode

Ussop - Vs in Single Player Mode

Gallery
Beat the game once with any character.

Hard Mode
Simply finish the Single player mode in Normal difficulty to unlock the Hard mode.

Time Attack
Beat Very Hard Difficulty to obtain The Time Attack Mode

Very Hard difficulty
You'll have to finish the Single player mode in Hard difficulty to unlock the Very Hard one.

Here's some gameplay footage from a pretty neat title: