Ikari no Yousai [Model DMG-IYJ]

Players switch:
During the game, hold Up, then press Select + Start to instantly switch between players without need to go to the options menu.

Secret message:
At the GAME MODE SELECT screen, enter SOUND BOY mode. Choose PROGRAM PLAY mode and set any sequence of the music tracks to play. Start to play the program either in THROUGH or REPEAT modes, no matter. There is a piglet character walking on the screen all the time the music is playing. At some point, this piglet will stop and make a bow to the player for a very short time. Press A + Start at exactly that moment. This may be tricky, but if done right the message "BU !" will appear above the piglet. Need to mention, SOUND BOY actually was written for another game: "Hero Shuugou!! Pinball Party". The piglet and fire heads are characters from that game.

Secret passwords:
Note, that there are no infinite lives/ammo passwords, only large amount of it at start. Also note, the second portion of passwords has a dupes with exactly the same effects but different names. Also all these passwords causes a HUD glitch if simple players switch button (Start) is used for the very first players switch on the level.
Always start as male, default parameters.
CCCC (for the Japanese version) - Stage 1
TANK (for the Japanese version) - Stage 2
DRAG (for the Japanese version) - Stage 3
COMP (for the Japanese version) - Stage 4
For the Japanese version only
Extra 240 medkits/bullets, max lives/bullets, flame thrower weapon.
AAAA (Male) BBBB (Female) - Stage 1
GUN? (Male) JEEP (Female) - Stage 2
CANO (Male) BIO! (Female) - Stage 3
BOMB (Male) ROBO (Female) - Stage 4
Always start as male, chibi female mode, default parameters.
Simple players switch button code enabled: Start.
Stage skip cheat enabled: hold Down, then press Select + Start.
YURI - Stage 1
KEI! - Stage 2
AMI! - Stage 3
RIE! - Stage 4
Chibi female mode.
Extra 240 medkits/bullets, max lives/bullets, flame thrower weapon.
Simple players switch button code enabled: Start.
Stage skip cheat enabled: hold Down, then press Select + Start.
MINT or YOKO or MIA! (Male) MOMO or MAMI (Female) - Stage 1
ELI! or RISA or GAMI (Male) EMI! or JUN! (Female) - Stage 2
REI! or KAYO or RIKA (Male) MAI! or TAE! (Female) - Stage 3
SAKI or RUMI or ERI! (Male) YUU! or NAMI (Female) - Stage 4