Gunners Heaven

Cheat mode:
Watch the opening demo run until it completes. Press and hold L1 + L2 + R1 + R2 and press Select on controller one when the title screen appears. The "Push Start" text will change to "Secret Code" to confirm correct code entry. Note the two letters behind the "Secret Code" text. Press Up or Down to change the left letter. Press Triangle or X to change the right letter. 

Code	Effect
MA	Start at Stage 2.
UT	Start at Stage 3.
RH	Start at Stage 4.
MK	Start at Stage 5.
HT	Start at Stage 6.
CM	Small character (does not alter hit check size).
QB	Large character (does not alter hit check size).
MV	Press X, Square, O, Circle on controller two for smaller windows on screen.
YI	Start with nine bombs.
TY	Axel or Ruka can kill with one hit.
SS	Weapon power-up time starts at 999 seconds.

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Debug mode:
Set code to MA, press Select, change code to SV, and press Start. Press the following buttons on controller two:

Button	Effect
Up	Boosts weapon power to maximum for ten seconds.
Down	Toggle voice mode.
Left	Change Gunlock type.
Right	Skips area and disengages Invincibility.
Triangle	Toggles Invincibility (falling will still cause damage).
Circle	Increases number of bombs.
Square	Switches selected weapon type between Axel and Ruka.
X	Increases weapon power up time in 30 second increments.

출처 : http://www.gamewinners.com/playstation/GunnersHeaven.htm