Shin Seiki Evangelion: Mahjong Hokan Keikaku

Shin Seiki Evangelion: Mahjong Hokan Keikaku
Developer: Studio Saizensen Publisher: King Records Platform: Game Boy Color Released in JP: September 29, 2000 This game has hidden development-related text. This game has a hidden sound test. This game has hidden bonus content.

You can't have a party without mahjong!

Unadvertised Cross-Game Multiplayer Mode

Shinseiki Evangelion: Mahjong Hokan Keikaku is built off the same game engine as Broccoli's other mahjong games, Dejiko no Mahjong Party and Kidou Senkan Nadesico Ruri-ruri Mahjong, sharing UIs, the majority of non-character-related graphics, and game systems.

Rumors surrounding the possibility of a Cross-Game link for multiplayer matches between these games existed through the 2000s, which in March 2015 Japanese Twitter user IkamanS2 demonstrated were in fact true.

Sound Test

Game Genie code 091-D3F-F72 will start the game in a sound test.

Development Related Text

Located at 0x38000 is development text implying that debugging features existed at one point:

CHR02
CHR03
CHR04
CHR05
CHR06
CHR07
CHR08
CHR09
CHR10
CHR11
CHR12
CHR13
CHR14
CHR15
CHR16
CHR17
CHR18
CHR19
CHR20
CHR21
INIT
PLC01
PLC02
PLC03
PLC04
PLC05
PLC06
PLC07
PLC08
PLC09
PLC10
PLC11
PLC12
PLC13
PLC14
PLC15
TIME
FREE
PLC16
PLC17
PLC18
PLC19
PLC20
PLC21
PLC22
CARD
CONTINUE
DEBUG
GAMEOVER
NAZENANI
SERIAL
STARS
THIRDDAY
SEC_DAY
APOSTLE

The below is present at 0x15F641, 0x15F670, and 1,091 other places in the ROM:

PRTCHR

(Source: nensondubois)