Fighting Vipers 2

Full pause screen -
Press X + Y, while paused the gameplay.

Change outfits:
Go to the fighter selection screen, highlight a character and
press Down or Up.

Powerful punch: Hold Back and press X
Powerful kick: Hold Back and press Y

Charlie's bike:
During the gameplay with Charlie, press Down, Down.

Bonus stage
Finish stage 7 in random or arcade mode in maximum 5:50 time
with minimum half of your strength remaining or a Super K.O.

Unlock Kuhn as playable character:
Beat Mahler in arcade mode with Super K.O.
or
maximum 5:50 time with minimum half of your strength remaining
After, beat Kuhn in the extra stage.

Unlock B.M. as playable character:
Beat B.M. in random or arcade mode with a Super K.O.

Unlock Del Sol as playable character:
Beat Del Sol in random mode and finish the game.