Deadly Arts 

Note: This game is also titled G.A.S.P. Fighter's NEXTream.

Play as Reiji 
At the title screen:
press A, B, Right, Left, Right, Left, Down(2), Up(2). 

Play as Gouriki 
At the title screen:
press Up(2), Down(2), Left, Right, Left, Right, B, A.

Serect stage 
Break down all ten buildings in a single stage. Then, return to the stage selection screen and press Start.

Extra character creation bodies 
Create and train a character until he or she has accumulated over ninety moves. 
Then, two new bodies (male and female) will be unlocked the next time the 
character creation feature is used.

Regain health 
After being knocked down:
repeatedly tap C-Up, C-Down, C-Left, or C-Right to regain up to two health points.

Alternate costumes 
At the character selection screen, hold L and press Left or Right. If you 
entered the code correctly, the character portrait will change colors. Then, 
select a character while L is still held.