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Touhou Reiiden: The Highly Responsive to Prayers is the first game in the long-running Touhou series. Being a PC-98 game, it never gained much recognition outside of Japan, and is now mainly notable for being the only game in the mainline Touhou series that isn't a vertical shooter.

Fortunately, ZUN found a better formula shortly afterward with Story of Eastern Wonderland, and the rest was history.

Unused Music#

ZIPANGU.MDT is an unused music track, titled "Shrine of the Wind" in the game's music test. It is also the only track from the PC-98 Touhou games not to be remixed for Mystic Square, and does not appear on any of the official soundtrack albums. Strangely, this track will play if an invalid stage is entered in the stage selection screen. It could be a fallback for when there is no music associated with a stage.

Bomb Option#

Unlike several later games in the series, The Highly Responsive to Prayers lacks an option to select how many bombs you start with. However, the setting still exists in the (non-human-readable) configuration file, suggesting it once was or was planned to be an option at some point.

Open REIIDEN.CFG in a hex editor and change the ninth byte to between 0 and 5 to change the initial number of bombs.

Debug Features#

The game has some leftover code used for debugging, consisting of an in-game display and a memory info screen. These can be activated by starting the game with an additional command-line parameter from the DOS prompt:

Note that quitting a game in progress will cause all of these to be disabled.

Test Mode#

Enabling test mode allows you to automatically finish the current stage by pressing Return.

Also, pressing Roll Up (PgUp) during gameplay displays a screen with information about currently allocated memory. The available actions here:

• Z - frees all currently allocated memory for panel graphics. This causes any further panels cleared to draw garbage onto the screen instead of revealing part of the background.
• X - frees all currently allocated memory for boss graphics, resulting in garbage sprites appearing during boss battles.
• Up - clears all bullets from the screen.
• Down - unknown.
• Return displays another screen with info about specific memory regions.
• Roll Down (PgDn) - returns to the game. Sometimes, two presses are required for gameplay to resume fully.

Debug Mode#

In debug mode, some game state information is displayed under the status bar:

• gx is Reimu's current onscreen position.
• coreleft is the amount of remaining memory available to the game.
• HEAP Cheak displays the status of the free store (empty/OK/corrupt).
• kbhit: unknown.
• dir is the player's current direction of movement or 0 if standing still.
• sp is 1 if the player is currently firing, 0 otherwise.
• sh is 1 if the player is currently swinging, sliding, or otherwise using the X button, 0 otherwise.
• exit: unknown.
• end is 1 during end-of-level sequences and game over screens, 0 otherwise.
• main increments constantly, resetting to 0 after the player performs an action (at the end of the animation).
• rand is a frame counter likely used for random number generation.
• bomb increments constantly, resetting to 0 as soon as the player performs an action.
• timer measures the number of frames that have elapsed in the current stage, occasionally followed by one or two more digits of unknown purpose.

Unused stages#

When using the stage selection mode, if the player inputs an vaule higher than 19, the game shows an hidden stage with the red colors swapped to green. After passing this stage, the game crashes, showing the cards of the next stage flipping.