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February 29, 2024


Everything about MSX, and more…

Zanac A.I. (ザナック)

17 min read
An arcade-style shoot 'em up game where the player flies a single starfighter known as AFX-6502 Zanac through twelve levels to reach and destroy the "System" — a part-organic, part-mechanical device created by a long lost alien race — which threatens to destroy Mankind after humanity tries (and fails) to harness its power.

Zanac is a unique shoot ’em up game highly advanced for its time, combining gameplay elements from successful franchises such as Xevious, in which the most noticeable similarities lie in the extensive power-up system and the vertical-scrolling gameplay that features both air and ground targets. However, the distinguishing aspect of Zanac is its unique enemies artificial intelligence, called at the time the “Automatic Level of Difficulty Control“, which auto-tweaks the System’s aggressiveness and the game’s difficulty depending on the player’s abilities, such as attack pattern and skill level.


Millennia ago, an unknown alien race created a tiny device known as the “System” containing boundless wisdom and knowledge. The artifact was protected by a safety mechanism capable of unimaginable destructive power. If properly disabled through the riddles, it would grant access to untold enlightenment and technology, but if improperly accessed it would unleash unlimited levels of havoc and destruction.

It was when humanity began traveling into space and exploring other worlds when they found the ancient artifact. Without understanding the device’s history, scientists naively attempted to hack into it and failed, triggering its defenses. From that tiny Icon, the destructive forces spread throughout all known areas of space, conquering and destroying all in its path, posing a mortal danger to all life in the universe.

Zanac Ship
The AFX-6502 (AKA “Zanac”)

Countless desperate attempts were made to fight or contain the System Defenses, but nothing seemed to be able to overthrow its power, not even the most powerful fleet of fighters ever assembled.

The same scientists who unleashed its power, also discovered that the defense system was designed to overcome massive attacks and fleets. In theory, they believed they found a flaw in its strategy. Based on their learnings, they estimated one lone starfighter would not be considered a major threat by the System, allowing a capable enough pilot with a powerful enough craft to punch his/her way into the heart of the System to destroy it.

Then, with everything that was learned from the previously failed attempts, the AFX-6502 (AKA “Zanac“) was built, and you were chosen to be the pilot to fly it through the System Defenses and save the universe.

The ship is simply the most advanced starcraft ever produced. A small vessel for a single pilot that was enhanced with the capacity of integrating some of the weapons and technologies released by the System along the way, which can eventually be used to destroy the ancient intelligence once its core has been reached.


In the game, you control the spaceship AFX-6502 as it flies through various planets, space stations, and outer space through an armada of enemies comprising the defenses of the game’s main antagonist — the “System”. Your mission is to fight through eight long levels and find your way into the System Core to destroy its defenses and eliminate its ancient intelligence.

Along the way, you will have to shoot down opponents while destroying enemy projectiles and terrestrial bases. Time after time you will find compatible weapons you will be able to integrate into your craft and enhance it, while allies will try to help by sending your way capsules (pods) that may contain additional enhancements and lives. 

There are also totems (bolder statues) that may release energy balls that you can use to destroy all enemies in range. Some of those energy balls also hidden keys to access secret levels or jump to different areas of the game. You just need to wait long enough to see if the bright ball will turn black or simply vanish.

Game tip: the only way to access the eighth and last level of the game to destroy the System AI Core is by finding the right totem in level seven that will release a power ball with a hidden key to access the hidden level eight. Otherwise, level seven will be an endless loop.

The game starts with three lives. After losing a life, gameplay continues with the player reappearing on the screen but losing all previously accumulated power-ups. Because the action does not stop, the player reappears with temporary invincibility.

The game ends when all lives have been lost (of course) or after completing the eighth and final area. However, the player can earn 1-ups (extra lives) throughout the game by accumulating high point scores or finding additional life pods. In addition, Zanac has a continue option that allows players to restart the game from the level at which they lost their last life.

The ship is initialized with a rapid-fire main cannon, which can be upgraded by collecting power-ups found in triple-boxes that periodically descend from the top of the screen. But, be careful, not all boxes have enhancements. Some may have nothing, some may be a trap!

As the main cannon’s power level is upgraded, the number of bullets fired – as well as their speed – increases. In addition to the rapid-fire main cannon, the ship is also equipped with a specialty exchangeable weapon that can integrate with the System’s alien weapons and that can be fired independently from the main cannon.

There are eight different specialty weapons, each represented by a differently numbered power-up and color. The player can change the type of specialty weapon equipped by collecting a differently-numbered power-up. The specialty weapon can be upgraded by collecting a numbered power-up that matches the one in use. These weapons range from a variety of different styles, including directional bullets, shields, indestructible projectiles, and phasers.

Below are the different weapon types and their maximum levels:

Weapon Number and NameMaximum Level
 Main Cannon – Rapid-Fire4
 Specialty Weapon 0 – All Range Phaser3
 Specialty Weapon 1 – Straight Crusher5
 Specialty Weapon 2 – Field Shutter5
 Specialty Weapon 3 – Circular5
 Specialty Weapon 4 – Vibrator5
 Specialty Weapon 5 – Rewinder10
 Specialty Weapon 6 – Plasma Flash4
(Level 5 is a one time special)
 Specialty Weapon 7 – High Speed5

The entire gameplay experience can be seen in this LongPlay video by the World of Longplays:


The name “Zanac” is an anagram for “Nazca”. The mountains-and-plains setting is practically identical to Namco’s Xevious, released two years before, which featured the mystical Nazca Lines from southern Peru. Zanac doesn’t have these, but a similar setting is apparent. This connection only applies to the MSX release though, as the later versions substantially changed the game’s appearance.

The game story of Zanac follows the E.I. – Exa Innova story style. It was a similar, yet primitive game released in 1983 by Compile when it went by the name Programmers-3. It depicts some common enemies with Zanac and a cruder version of Zanac’s famous Artificial Intelligence.

The game AI is called the “Automatic Level of Difficulty Control” or ALC (no, it is not ALDC, it is indeed ALC). This innovative technology can make every game experience different due to its sophistication. The ALC measures the System’s aggressiveness and the game’s difficulty depending on the actions of the player, such as attack pattern and skill level. The ALC increases for experts but decreases for inexperienced players. For instance, shooting the main cannon frequently, collecting power-ups, and destroying bosses within the specified time limit increases the ALC, resulting in a greater number of tougher enemies appearing on the screen. Basically, if the player fires more, the AI reacts by sending more powerful enemies. However, actions such as losing lives, starting a new level, or destroying reconnaissance pods in a bad timing reduce the ALC, resulting in fewer on-screen enemies.

Zanac was officially and non-officially released multiple times for the MSX system before debuting on other platforms.


The Original Version

Original Cartridge Version:

Original Tape Version:  

Zanac A.I. was created by Compile and released in 1986 by Pony Canyon as a cartridge game in Japan. Later the same year it was released in Spain in cassette tape format.

There are very few but noticeable differences from the original cartridge version to the tape version. The most perceptible is the “AI” logo in the opening credits, which in the tape version appears written in light green using a styled font, while in the original version it uses the same font and color as the rest of the texts in the game. 

The logo itself strongly varies in the product boxes in between both versions. The tape has the game name written in common condensed font instead of the game logo as it appears in the Japanese cartridge version. 

Beyond that, there are very very few other discrepancies, mostly noticeable in the game map, in the distribution of the enemies, and in the score panel.

Zanac 2nd Version

Beyond the original releases, there was a non-official Zanac AI 2nd version release that entirely differs from both original versions. While the game, ship, weapons, and enemies are unchanged, the gameplay and the map are all quite different. Here some of the most noticeable differences you may encounter in the Zanac 2nd version:

  • It features 12 rounds instead of 8
  • It is harder
  • Many scenes and scenery are totally different
  • The music pace is faster on the 2nd version
  • The last round (12) is drastically shortened if compared with the last round of the original version (8), only featuring the final boss.

In addition to all that, several different variations of the 2nd version exist with the opening credits altered (examples below). Also in the final credits the name “MASAKAZU MIYAMOTO” is replaced by “PRESENTED BY PONY” but missing the “INC” designation.

Zanac original cartridge version opening

Zanac 2nd version modified from tape release

Such discrepancies can also be found in the original version of Zanac, most likely from outside Japan, in which the texts “GAME DESIGNED BY COMPILE” and “PRODUCED BY AII” sometimes can be found as “GAME DESIGN BY COMPILE” and “PRODUCED BY AAI” (instead of “AII”).

The true origin of the Zanac 2nd version is unknown. In 2017, Satoshi Fujishima (designer of games like Guardic, Gulkave, and Golvelius) was found discussing via Twitter about the game with its creators, Masamitsu Niitani (Moo) and Takayuki Hirono (Jemi), and the conclusion was that that the Zanac 2nd Version was a fake release re-engineered from the tape version (because the AI logo is the same as the tape version). They all confirm that no “official” 2nd Version was ever created, nor released, either by Compile or by any one of them.

Here you have a great video from MSX Wiki demonstrating the gameplay experience of the Zanac A.I. 2nd Version:

Zanac 3

In the middle of all that confusion, there is also a 3rd version of the Zanac game, which is a Hack (Cracked version) created by Magicracks. They intended to release the game as an upgrade, but it was considered bad in general, having problems in the element colors and mediocre playability. 

Additional opening image from Magicracks

Zanac 3, modified opening credits

Check out this video demonstrating the experience provided by the Zanac 3 game version:

Popularity and Continuity

Zanac is a memorable game that was ported and heavily reworked for other platforms. The game was so popular that soon after its debut in the MSX system it was ported to Nintendo Family Computer Disk System (FAMICOM) and NES, among other systems, and including less capable ones such as the PalmOS.

The PalmOS port of Zanac

The game Experience on PalmOS (no sound)

Other Releases

Yet in 1987, the same year Zanac was released for MSX 1, it was officially reworked by Compile itself and released for the MSX 2 system as Zanac EXt, now recolored and featuring improved graphics, smooth scrolling, and extended music over the original version. It was very similar to the Famicom version, albeit with different colors, and at a noticeably slower pace.


In 2001 Compile once again resorted to Zanac’s reputation and success and released a compilation titled Zanac X Zanac for Sony’s PlayStation in Japan. Then, in 2007, the NES version was re-released for the Wii Virtual Console by the D4 Enterprise.

For Compile, the game Zanac – together with Puyo Puyo – was a very important product that helped the company to gain a reputation among Game Producers in Japan and open a profitable market worldwide. Utmostly, Zanac is one of MSX’s most classic and well-known games, loved by many, and yet today a challenge for most.