Tool-assisted game movies
When human skills are just not enough

Submission #1124: JXQ's NES Moon Crystal in 08:43.62

Console: Nintendo Entertainment System
Game name: Moon Crystal
Game version: Japan
ROM filename: Moon Crystal (J).nes
Emulator: (unknown)
Movie length: 08:43.62
FrameCount: 31417
Re-record count: 11643
Author's real name:
Author's nickname: JXQ
Submitter: JXQ
Submitted at: 2006-07-16 23:26:50
Text last edited at: 2006-07-20 13:37:42
Text last edited by: Bisqwit
Download: Download (2298 bytes)
Status: published
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Author's comments and explanations:

Moon Crystal TAS by JXQ (v2)


This run satisfies the following criteria:

  • Aims for fastest time
  • Uses damage and death to save time
  • Abuses programming errors

  • Emulator Used: FCEU 0.98.16, last improved by Luke


NrgSpoon introduced me to this game. It's a gem of a platformer released only in Japan. The controls have some Prince of Persia in them, but are not as demanding. The music is great and the graphics are pretty good. I'm surprised the game was never ported to the US or Europe.

About the Game:

Since most will probably not be familiar with this game, here are a couple things worth mentioning.

There are treasure chests littered throughout each level. Most of the powerups are not needed in a TAS (such as extra lives, hearts, or heart expansions). There are two exceptions, however. One being the winged boots, which allow a mid-air jump, and the sword, which allows for a longer range and increased attack power on the original weapon. The increased attack power is only shown when life is down to one heart remaining. A jumping slash will then inflict three hits on bosses if aimed properly. This is why some levels take damage even when it may not seem obvious as to why.


It isn't noticeable when watching, but there is a jumping glitch used throughout. There's a point where jumping to a platform will change the animation to "standing", but not actually land on the platform. However, this allows a one-frame window to jump again.

Instead of turning around on the ground, time can be saved if it is done in midair, even if it requires an extra jump.

Bosses have a peculiar way of telling the game when they are allowed to be hit again. If, after hitting a boss, you do something to cancel the sword-swinging animation, the "I can be hit again" flag will not reset until the sword is swung again. This is a nasty bug that makes jump-slashing during bosses a pain, but viewing the contents of memory location 061F allowed me to make sure every hit also made the next hit ready. This is more like...avoiding programming errors, I guess.

If death occurs after a boss is finished exploding, the game immediately jumps to the next cutscene about five seconds faster than waiting for the screen to fade out.

Improvements from Previous run (which is here)


  • Used a faster method when recovering from damage. This allowed the power sword to be faster in more levels.
  • Used jumping to turn around when possible.
  • Overall, 563 frames faster than my previous attempt.

Level 1

  • Thanks to Guybrush for pointing out the other pair of boots that save time climbing later.
  • Different strategy against the boss.

Level 2

  • Took boots at different time.
  • Used power-sword against boss.

Level 3

  • Different branch jumping.
  • Used power-sword against boss.

Level 4

  • Took hits at better times.

Level 5

  • Better manipulation of falling rocks.
  • Reduced lag in second falling rock section.

Level 6, part 1

  • Took a heart in order to use damage to save time one more time.
  • Different strategy against second boss.

Level 6, part 2

  • Jumped onto closer side of floating platform.
  • Better manipulation against boss.

Level 7

  • Took damage in better places.

Other Points of Interest

Level 1

  • It is actually one frame faster to take two hits and get the sword powerup, but it affected lag badly in the second level.

Level 2

  • This is the only level where jumps boots are not required to complete the level. However, grabbing them saves several grabbing and climbing ledges, so they end up saving enough time to be worth grabbing.

Level 3

  • The switches in this level open up gates shortly after for a brief period of time. You can hear them close after passing. (Clang)

Level 5

  • Jumping is used often to avoid the turnaround animation when changing direction while descending.

  • I tried to take a final hit on the spikes above to save time after the boss exploded, but they are too high.

Level 6

  • Around frame 24950, the shortcut here I believe was not meant to be possible. The normal way is to go up and around the stairs to another room.

Suggested Description & Screenshot:

Moon Crystal is a game that was only released in Japan. It features good controls that are reminiscent of both Prince of Persia and Ninja Gaiden, and being a late NES release, it has great music, graphics, and animation for its time.

The bosses of this game can be difficult due to a glitch that improperly resets the boss's vulnerability after being hit. You could say this run "avoids programming errors".

Good screenshot: Frame 7479.

Thanks to...

NrgSpoon, who (1) introduced me to the game, and (2) told me about the power-sword technique. Guybrush, who spotted the error that finally convinced me to redo this run.

adelikat: Good job, accepting.

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