At the title screen, press Up 17 times, then Start. Now enter the Options screen. Dural's stats are now on the Records screen. You can also play as Dural in Vs. Mode.
Change Ring Size and Level Select
At the "Press Start" screen, press Up 12 times, then press Start. Now enter the Options screen, highlight "Exit" and press Down, A.
Freeplay Mode
At the title screen press X + Y + Z. You will read the words "Freeplay mode" at the bottom-left side of the screen. What this code does is it disables pausing during the game. It also changes the words "LICENSED BY SEGA" etc. at the title screen to a different font.
Hidden Options Menu
At the Title Screen, press UP 12 times, then press START.. Go into Options and move the cursor off the bottom of the screen to uncover the Hidden Menu.
Play as Dural
At the character select screen, press Down, Up, Right, Left + A.
Ranking Mode
At the title screen, press Down-Right + C + L + R + Start.
Vs. Mode - Character and Level Select
After a "Vs." match has been completed, press L + R to access a menu which allows you to select your character and level.