There are lots of cheats and secrets to unlock in Soul Calibur, here's some of them.
Not really a cheat, but to change character's costumes, hit Y while choosing your character.
Unlock Hidden Characters
To unlock the hidden characters, you must finish arcade mode with every character to unlock one new character for almost every one you solve it with (beating the game with some characters won't unlock anything), plus hidden stages. These characters are Hwang, Yoshimitsu, Lizardman, Siegfried, Seung Mina, Rock, Cervantes. The final character to be unlocked is Edgemaster, who will show up after you beat the game with all players, including the hidden ones.
Solving Mission Battle
Finish all the missions in Mission Battle and you will get all the hidden art in the museum, plus extra clothing for Sophitia, Voldo, Maxi, Siegfried, and Xianghua by pressing Y + A at the same time on the controller when selecting a character. You can also unlock more things in the museum like exhibition theater, intro edit mode, more backgrounds, and another survival mode. After obtaining all 338 pictures from the Art Gallery, a new Black and White title screen appears. If you beat every mission in Mission Battle, it will have a gold tint.
Play as Inferno
To unlock Inferno, go to the Art Gallery and open picture #39. This unlocks Xianghua's third costume. Play through Arcade Mode using it (after unlocking all the other characters, including Edgemaster), and Inferno becomes available. If you complete arcade mode with Inferno, the title screen changes.
When you unlock Edgemaster and beat all the missions in Mission Battle you will get extra weapons when selecting your characters by pressing L.
After unlocking Edgemaster, you can play as the "Unknown Soul" version of your character by holding R when you select him\her or her. This will make your character transparent.
To activate Metal Mode, first earn the option via the Mission Battle. Then then while selecting your character, hold R. Now you're shiny.
To access hidden missions in Mission Mode, move to the peninsula above japan where it looks like a T-shaped mountain range.
The cursor should click into place. This
gives you five extra missions. Two more
missions are on the far left map in the
upper right. Accessing these missions
changes the title screen background.
Water Vein Mission
After you beat the game as Lizardman, the Water Vein mission shows up.
Tired of looking at the winning character gloat? Press B to focus on the losing character.
Select Victory Pose
After winning a match, you can select your character's victory pose by pressing B, X, or Y during the replay.
Sophitia's Underwear Code
To change the color of Sophitia's underwear, continually press one of the following button combinations, each for a specific
color during the selection screen until
Sophitia does her pre-battle pose: "X" "Y",
"B", "X + B", "X + Y", "Y + B", "X + Y + B".
Visit this Game's Dreamcast Database Entry
Got any more cheats? Let us know.