Double Dragon II: The Revenge (NES)

The Lee twins put their differences aside to take on a far deadlier foe, who quickly makes things that much more personal. This NES port brought back the co-op feature inexplicably missing from the first game, as well as some funnier-than-intended cutscenes. G - R - A - S - P !

Debug features
There is a common debug feature in a couple of Technos games. Usually all debug code is controlled by a memory flag, hardwritten at the end of the ROM at address in M6502 CPU address space. Various bits of this variable enable or disable various debug features.

Sample version
Bit 7 of the debug variable (to set it, use the Game Genie code ) switches between normal and "SAMPLE VERSION", which enables some debug features. During the game, hold the Select button on Controller 1, then press one of the following buttons:
 * Up / Down: Gets rid of the nearest enemy on a particular side.
 * B: Gets rid of all enemies on the screen.
 * A: Instantly takes you to the next level.

Free walk
Bit 5 of the debug variable (to set it, use the Game Genie code ) enables free walk mode, which allows you to walk to any part of level instantly.

Marian


Three different standing sprites were drawn for Marian for her brief in-game appearance in the beginning of Mission 9, but only one was actually used. The final sprite can be seen on the left, while the two unused designs are on the right.



A screenshot from an early version, published in the Double Dragon III manual of all things (in a section where they summarize the plot of this game), showing one of the unused designs for Marian with a different color palette.

Title screen
"Acclaim presents" was added to the top of the NES version's title screen, causing the logo itself to be moved a bit lower and a single line of copyrights removed.

Copyrights screen


All the copyrights information have been moved to a different screen in the NES version, which is displayed just before going into the main menu.

Difficulty settings
The difficulty choices are aligned horizontally in the FC version and vertically in the NES version. Because of this, players can adjust the game's difficulty by pressing left or right on the d-pad in the FC version, a leisure not available to NES players. In addition to having fancier names in the NES version, the difficulty settings in the NES version also limits the game's length. The NES version allows the player to clear only the first three stages on the "PRACTICE" difficulty level and eight stages on "WARRIOR". The FC version allows player to clear all nine stages on any difficulty setting. Enemy characters seem to have less health on the NES version's "SUPREME MASTER" setting than they do in the FC version's equivalent "DIFFICULT" setting.

Continues
The FC version allows you to continue after a game over by default. The NES version doesn't have continues normally, but you can use them with this cheat code. At the "GAME OVER" screen press one of the following combinations to enter "Continue" mode and start again from the last level.
 * on first controller Up, Right, Down, Left, A, B: For Missions 1-3
 * on first controller Up, Down, Left, Right, B, A, A: For Missions 4-6
 * on second controller A, A, B, B, Down, Up, Right, Left: For Missions 7+

Mission 1 opening sequence
The opening cutscene of Mission 1 ends a bit differently between both versions. In the FC version, the opening ends with a wide closeup of Billy's eyes on a yellow background with text underneath, whereas in the NES version it shows a narrower closeup of Billy's eyes, followed by a visual of him screaming in anger while clenching both fists.

Mission 6
In the FC version, the disappearing platforms have different patterns depending on the difficulty level: on Easy, all the platforms will appear at the same time, making these jumping sessions easier; on Normal only two platforms appear at time; and on Difficult, only one platform at a time. For some reason this differences in patterns was removed in the NES version, where only one platform appear at a time, regardless of the setting.

Regional left-overs
Both versions of the game contain a lot of disabled code left-overs from the other regional version. Although it is not possible to completely switch any game to another language mode, it is possible to switch between the two different sets of features in various places to change game behaviour between Japanese and US modes. Typically, the code pattern for such disabled code branches is which translates to the instructions "LDA #$XX" and "BEQ $", which means that the branch will always happen if  is zero or always not happen in other cases. For the Japanese version,  is all zeroes, while for the US version  is. Since you can only disable some of the screens and modes in US version with these codes, it's not very interesting. However, you can re-enable some things in Japanese version that are different from the final US version.

Different title menu
The Game Genie code re-enables an earlier version of the title menu for non-Japanese versions of the game. Note that full title of the game was meant to be "Revenge of the Dragons."

Glitched copyright screen


The Game Genie code re-enables the copyright screen from NES versions of the game, but because of incorrect CHR bank settings, the text displayed becomes Japanese gibberish. Note that the screen in this version has different colors.

Difficulty limits


The Game Genie code re-enables the difficulty limits in the Japanese version. Messages for both difficulties are mostly similar to the final US version, with only one difference - they call you "DRAGONS", instead of "DOUBLE DRAGONS".

Unused messages


This screen's meant to be displayed after you beat any game mode, but currently only strings are left in the internal strings table for both versions. You can only see this string using debugging.