X

Prototype Info Prerelease Info Notes

Debug Inputs#

Press B, Right, B, A, Down at the title screen to wipe the save file.

While paused on the surface of Earth or Tetamus II, press B, A, Down, Start, A, Right, B, Up, Right, Start to trigger the credits which add two stars to both sides of the "Press Any Key" text on the title screen permanently.

Unused Item Shop#

Use Game Genie code 03E-E58-F7E and enter any regular ground base to see what appears to be an early Item Shop, with Fvarg; an alien character who doesn't appear in the final game. Interestingly, this text is still in English.

There is more code and data to draw an actual shop environment and actual item selection, but most of it is unreferenced at all and may be accessed via advanced hacking.

Unused Junction Shop Behavior#

By changing the byte at 0xC120 to 00 00 (Game Genie code 001-20B-E65), you will be allowed to re-enter the Military Store in the junction after receiving a pickup from it, with a handful of otherwise-unused English text at 0x16B3B now utilized to give the player messages if certain pickups (or all of them) are out of stock:

This Base Has Run
Out Of Supplies.
Out Of Missiles.
Out Of Fuel Supplies.
Out Of Materials

The line mentioning missiles also goes unused by this behavior, as the game mistakenly uses the Fuel Supplies line for that pickup as well.

Leftover Weapon Energy Mechanic#

For the primary weapon, energy will charge over time, and the weapon can only be fired if it's over a minimum energy threshold, depleting that much energy in the process. The threshold for the default laser, however, is set to 0, effectively disabling the mechanic altogether. 7 energy is recharged each game tick, and the byte at 0xE5E3 is the threshold. Game Genie code 285-E39-E6A will change the beam's threshold to $28, for demonstration purposes.

Inventory System Leftovers#

The item inventory system from the prototype is still present in the final game, albeit hijacked by the new equipment system. Slot 1 is set to Laser, and Slot 2 is set every frame based on equipped equipment, for use with the B button. Pressing Select to scroll through slots goes unused. Here are all of the items in internal order:

Any weapons dealing more than 1 damage overrides the check for if beams should damage particular entities.

Unused Sounds#

The "X" forming into position and title attraction sequence were supposed to play sounds, however it is likely they were disabled because the music volume was set way too loud, making the sounds barely audible. Game Genie code F53-50A-081 will enable the unused sounds, while Game Genie code 292-01F-E6E will play the sounds without music.

Unused Ending Screen#

There are two identical copies of staff credits at 0x22B69 and 0x391F5 (the latter is actually used, another one is a part of a large block of BANK E data copied to BANK 8). Both of them contain an unused part started at 0x22DD1 and 0x3945D correspondingly which appears to be planned for use in the US version:

LUNAR CHASE WAS BROUGHT TO YOU BY NINTENDO 1991

You may even see this message in action in the final version. Activate Game Genie code 0FC-65D-E6A and then use the Staff roll cheat mentioned above.

Totaka's Song#

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This game contains the first instance of composer Kazumi Totaka's famous musical signature.

Play Mission 4 and rescue a fake scientist, wait around 45 seconds on this screen and Totaka's Song will play.

Objects List#

At 0x9228 Is a list of every object in the game (Not every model, though. some of them are called by functions rather than objects, or an object may call more than one, Like Sprog and Homing Missile). Of the 88 models, only 59 are utilized in the final game. Unused objects are marked with a * here. Objects that no longer have models are marked with **. Objects that appear out of bounds are marked with ***.

CUBE
TANK 
RADAR 
GAMEBOY 
GUN 
PYRAMID 
SFX GLIDER 
HOMING BEACON 
BOMB 
BIRD SILO
MILITARY BASE 
POWER CRYSTAL 
PETRIFIED TREE 
HOMING MISSILE 
PENDULUM *
SPROG *
MINE 
NUCLEAR SILO 
MUTATING PLANT *
ALIEN BASE 
CIVILIAN BASE **
SPROG *
INSECT THING 
COIN 
WAREHOUSE 
CRUISE MISSILE 
SPROG *
MUSHROOM 
SUPER GUN *
NUKE BOMB **
GAS CAN 
GAS STATION *
TRUCK 
ANOTHER TRUCK **
BLACK BOX *
TIME BOMB 
LITTLE MAN 
REACTOR ROD 
ARROW 
WALL 
GRASSHOPPER 
FLOWER *
LARVA 
MAN 
SCORPION *
TUNNEL ENTRANCE 
LIGHT TANK *
HEAVY TANK *
SMALL TANK 
SKIMMER 
CONE 
CRAB 
ROCKET LAUNCHER *
CHRYSALIS 
FLOWER *
SPIDER 
MOUSE 
COLLECT MISSILE 
TRANSPORTER 
SCENERY ONE *
SCENERY TWO ***
SCENERY THREE *
SCENERY FOUR *
SCENERY FIVE *
MINI RADAR ***
BUTTERFLY 
SCENERY SIX 
SCENERY SEVEN ***
PLANE ONE 
PLANE THREE *
PLANE FOUR 
SUGINO TANK FOUR *
ALIEN BASE 
DRAKE 
SLEDGE 
SUGI TANK ONE *
SUGI TANK TWO *
SUGI TANK THREE 
SUGI TANK FIVE *
DRAKE TWO *
SEA PLANE *
SCENERY EIGHT 
SCENERY NINE *

Unused Text#

There is a lot of unused text in English, presumably holdovers from mechanics that were scrapped before Nintendo translated the game to Japanese. These include leftovers from the original, unreleased Western version known as Lunar Chase (likely including the prototypes that were leaked). At 0xDE03 is some Crystal text:

ONE CRYSTAL WILL RESTORE YOUR SHIELD TO MAXIMUM
START CANCELS A  CONTINUES
YOU HAVE NO  CRYSTAL TO USE YOUR FUEL

At 0x12ACF are some leftover mission hints from the prototype, followed by some mission/tutorial descriptions. Notably, this lists 15 missions whereas the final game ends after the 10th:

HELP THE CRYSTAL IS LOCATED TO THE NORTHEAST FROM THE BASE 
HELP FOLLOW THE DIRECTION OF  THE TANKS BACK TO THEIR BASE
AND DESTROY IT 
HELP THE GUN FIRES MISSILES THAT TRACK YOU
FLY BACKWARDS AND SHOOT THEM 
HELP YOU ARE ON YOUR OWN FOR
THIS ONE GOOD LUCK 

MISSION ONE COLLECT ONE CRYSTAL
MISSION TWO   DESTROY FIVE TIME BOMBS
MISSION THREE  DESTROY THE HEAVY TANK
MISSION FOUR  FIND OUR SCIENTIST
MISSION FIVE   DESTROY THE ENEMY TUNNEL
MISSION SIX   ESCORT THE CONVOY OF TRUCKS
MISSION SEVEN  DESTROY THE FOUR GLIDERS AND COLLECT THE REACTOR RODS
MISSION EIGHT  DESTROY THE LARVA
MISSION NINE  DESTROY THE CRUISE MISSILE THAT IS HEADING FOR THE SILO
MISSION TEN  DESTROY THE BIG ALIEN BASE
MISSION ELEVEN  REPORT MINE FIELD SIGHTED FRIENDLY CRAFT STRANDED WITHIN OBJECTIVES
COLLECT PERSONNEL FROM STRANDED CRAFT AND RETURN TO BASE
MISSION TWELVE
TRAINING MODE
MISSION THIRTEEN  REPORT  MINES BECOMING A  MAJOR HAZARD OBJECTIVES
DETONATE ALL MINES WITH TIME BOMBS OR SIMILAR HIGH EX AND RETURN TO BASE
MISSION FOURTEEN  REPORT  MAJOR CLUSTER OF  ENEMY BASES SIGHTED EASTWARDS
EXTREME CAUTION OBJECTIVES SEEK AND DESTROY AND RETURN TO BASE
MISSION FIFTEEN  REPORT FORMATION OF ENEMY FORCES SIGHTED TO THE NORTH
EXTREME DANGER OBJECTIVES DESTROY ALL ENEMY AND RETURN TO BASE

At 0x28C95 is some further mission text:

FIND THE CRYSTAL  AND TAKE TO SILO  BEFORE THE ALIEN  DESTROYS THE SILO
THE CRYSTAL IS IN SECTOR YOU HAVE A CRYSTAL NOW GO TO THE SILO IN SECTOR
ENEMY HAS PLANTED FIVE TIME BOMBS  DESTROY THEM ALL  BEFORE THEY BLOW  
TIME BOMBS LEFT   HURRY UP  QUICKER QUICKER PLENTY OF TIME
HEAVY TANK IS ON  COURSE TO DESTROY ALL OUR RADARS  DESTROY THE
TANK RADARS REMAINING SITUATION DRASTIC  HURRY UP PLEASE
SITUATION SAFE MISSION 

At 0x0BA34 is a list of names and scores meant to be used as a default Hi-Score table. "Dylan" may be developer Dylan Cuthbert, while the others may just be joke names:

DYLAN
0,0,5,0,0,0,0,0
FRED
0,0,0,4,0,0,0,0
BOB
0,0,0,0,3,0,0,0
SUPERMAN
0,0,0,0,0,2,0,0
DYLAN
0,0,0,0,0,0,1,0

Unused Training Text#

At 0x30000 is a table of pointers to briefing sequences, the first eleven of which correspond to the mission order as well as the final brief before the credits.

The twelfth entry at 0x30016 is an unused training briefing, instructing the use of Power Cubes to repair Beacons, and showing the bonus pickups; the thirteenth entry is for completing the training. There is also a pointer table for story recap text at 0x28018, with its twelfth entry for the training mission similarly unused.

The texts that show up at the top of the screen at the start of each mission and whenever Select is pressed also has an entry for the Training Mission at 0x17E33, which never gets triggered.

Tunnels#

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The data for all the tunnels are at the top of bank 9, with four different tables throughout the rom referencing them: one for start of levels (this handles the tunnels from training to Tetamus II, resuming the story, and the final escape tunnel), one for the tunnels to and from the junction, one for the alien tunnels used in Mission 5, and a table for the autopilot demos shown at the title screen (which have some overlap with the other three). The junction tunnels table has an unused ninth entry pointing to the tunnel at 0x251A7, and there is an additional tunnel with the starting shutters (used in the first table's tunnels) that goes unreferenced by any of the tables at 0x24150. Game Genie codes 41F-AFC-E6B 50F-AEC-4CF will change the tunnel to Tetamus II to the unused shutters tunnel, and codes 51F-AFC-E6B A7F-AEC-4CF will change it to the unused tunnel from the Junction table.

The starting three bytes for each tunnel get loaded into ram that is never read from, and only the first seven tunnels in the data (not exclusive to any of the tables) have nonzero values assigned to them. Just before the strings for "GET READY" and "GO GO GO" used in the first tunnel table's start sequence, there are additional strings "BONUS" (0x3475) and "10 X TIMER" (0x347B), which may suggest that the three bytes are some sort of time limit or par time, with some reward for speed involving the scrapped score mechanics.

Two unused tunnel entity types exist, types 7 (a nonmoving barrier that modifies its fill pattern [swap nybbles, increment, and invert the centre four bits]) and 9 (displays a 3D string "TUNNEL X", where X is the current level, 1-indexed). Use code 091-47B-C4A to change the "Exit" entity at the end of the tunnel to Tetamus II to a type 9 entity.

Eclipse Screens#

At 0xA007, a fullscreen tilemap with run-length encoded tiledata is located, containing the title screen for Dylan Cuthbert's original tech demo, Eclipse, which led to the creation of X. The dumped prototype of X still carries the original name in the header, owed to the fact that Nintendo president Hiroshi Yamauchi had it changed at the last minute.

The background of this title screen is an edited version of a NASA photograph of Bruce McCandless II a few meters away from the Challenger space shuttle from February 7, 1984. He is known to have made the first untethered spacewalk, and this was also the first use of the Manned Maneuvering Unit (MMU); a nitrogen-propelled, hand-controlled device.

At 0xE7A3 is another tilemap set, laid out as a menu with a few options for play.

References#