Dr. Jekyll and Mr. Hyde (NES)

Dr. Jekyll and Mr. Hyde
Also known as: Jekyll Hakase no Houma ga Toki (JP) Developer: Advance Communication Publishers: Bandai (US), Toho (JP) Platforms: NES Released in JP: April 8, 1988 Released in US: April 1989 This game has debugging material. This game has a hidden level select. This game has regional differences.

Dr. Jekyll and Mr. Hyde is a game based on the 1886 novella The Strange Case of Dr Jekyll and Mr Hyde by Robert Louis Stevenson. It's as good as it sounds, assuming you really hated the book.

Debug Features

When the title screen menu cursor points to the "START" option, press B on Controller 2, then press Up, B, Right, Left, Down, Right, Left, A, B, Right, Select, B, Down, Start on Controller 1. During gameplay, on Controller 2, press A to skip the current level (up to the ending sequence) or B to switch between the Jekyll and Hyde modes.

Regional Differences

To do: The lone FAQ on GameFAQs talks about enemies being removed from the US version and changes to the ending, so there's probably a lot more to be done here.

Title Screen

Japan	US

Copyright text was added.

Unused Graphics

The original Japanese version of this game used a UNROM board with 128 KB of PRG ROM and 8 KB of CHR RAM. This board configuration allows graphics data to be loaded into the CHR RAM from the PRG ROM on the fly, instead of relying on a fixed graphics ROM. The PRG ROM itself contained 48 KB of graphic data.

When the game was brought to the US, the cartridge board was changed to use the MMC1 mapper with a 32 KB CHR ROM chip instead of CHR RAM. During the conversion process, the developers moved 32 kilobytes of game graphics from PRG to the CHR ROM. However, since the game originally had 48 kilobytes of graphics data, that meant 16 kilobytes were left behind in the PRG ROM. The PRG ROM size itself was not reduced, and the developers simply blanked out the first 32 kilobytes of graphic data moved to the CHR ROM. But they left the rest inside the US ROM, so we have at least 16 kilobytes of graphics data from the Japanese version left inside the US version, unused and inaccessible.

This is the reason they completely removed two original levels from the US version. Those dropped out 16 kilobytes of CHR graphics contained the background and sprite data for exactly two missing levels. And, since the PRG ROM size was not reduced, instead leaving the former graphic data part-blanked and part-unusable, that led to the strange situation where the US game has a larger overall ROM size despite losing a significant amount of accessible content.

Levels

Because of stripping 16 kilobytes of 48 kilobytes CHR data during the cartridge type switching process (see the section above), they had to remove two original levels. The US release also radically alters the flow of the first four levels.

• Level 1 (city)

• Level 3 (alley)

To compensate for all of this, the cemetery and town levels are repeated twice. However, the stages' enemies were not changed to fit, which leads to most of them spawning out-of-bounds. Making things even more complicated, the order of the levels was rearranged, as the chart below illustrates:

Stage	Japan	US
1	City	Town
2	Park	Cemetery
3	Alley	Town
4	Town	Park
5	Cemetery	Cemetery
6	Street	Street

Only the last two levels were left untouched between versions.

Enemies

The following enemies and NPCs are exclusive to the Japanese version.

Despite not being included in the game, the North American version's instruction manual still lists all of the enemies and describes them.

Because some of these enemies have their own theme, this also results in the NES version not using the songs, despite still being in the ROM.

Mysterious Silhouette

Japan	US

As the the last boss explodes, a small silhouette appears next to the crumbling cross on top of the church. The shadow appears to be a person hanging from the cross on the top of the church. The North America version changed the graphic to something that cannot be identified.

Ending

In the Japanese version, the bride waits for you outside the church's gate in the good ending. In the US version, she is not there.

Bomb Detonation Time

In the Japanese version, the bombs vary in fuse time by level. In the US version, the time it takes for the bombs to detonate gets progressively shorter on each level.

Music

To do: Upload music.

There are a few songs in the Japanese version that are used, but were cut from the US version, as some of the enemies were cut from the North American version.

In addition, there is an unused song. It sounds like it may have been used for one of the enemy themes, but no enemy uses it.

(Source: VGMPF)