Zanac, the player controls the spaceship AFX-6502 Zanac as it flies through various planets, space stations, and outer space and through an armada of enemies comprising the defenses of the game’s main antagonist—the “System.” The player must fight through twelve levels and destroy the System and its defenses. The objective is to shoot down enemies and projectiles and accumulate points. Players start with three lives, and they lose a life if they get hit by an enemy or projectile. After losing a life, gameplay continues with the player reappearing on the screen and losing all previously accumulated power-ups; the player remains temporarily invincible for a moment upon reappearing on the screen. The game ends when all the player’s lives have been lost or after completing the twelfth and final area. However, the player can earn 1-ups (extra lives) throughout the game by accumulating high point scores. Zanac has a continue option which allows players to restart the game from the level in which they lost all their lives.
The player operates a rapid-fire main cannon, which can be upgraded by collecting power-ups found in blue boxes that periodically descend from the top of the screen. As the main cannon’s power level is upgraded, the number of bullets fired from the ship as well as their speed increases. In addition, the player operates a specialty weapon that is separate from the main cannon. There are eight different specialty weapons, each represented by differently-numbered power-ups. The player can change the type of specialty weapon equipped by collecting a differently-numbered power-up or can upgrade their current specialty weapon by collecting a numbered power-up that matches their current weapon. These weapons range from directional bullets to shields to indestructible projectiles. Players lose all accumulated power-ups if they lose a life.
Gameplay on the NES versionEnemies in Zanac include meteors, various bullet-shooting enemy aircraft, bullet-resistant disks, ground turrets, and reconnaissance planes. The bosses consist of stationary fortresses consisting entirely of ground turrets. The player must destroy all these turrets within a specified time limit to score bonus points. Every stage has one or more of these stationary fortresses. In addition, large enemy ships acting as “mini-bosses” appear throughout the game. These ships are more resistant to the player’s weaponry; all bullets inflict minor damage and are repelled off the mini-bosses, which change color as they become more damaged.
The distinguishing aspect of Zanac’s gameplay is its unique enemy artificial intelligence, called the “Automatic Level of Difficulty Control” or ALC. 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 failing to destroy bosses within the specified time limit increases the ALC, resulting in a greater number of tougher enemies appearing on screen. However, actions such as losing lives, starting a new level, or destroying reconnaissance planes reduces the ALC, resulting in fewer on-screen enemies.
Gameplay of Zanac on the MSX, where the game first debutedThe plot of Zanac revolves around the “System”—a device figuratively similar to Pandora’s box. The System was created millennia ago by an unknown alien race. It contains boundless wisdom and knowledge, as well as vast destructive potential. If properly opened it would grant access to untold wisdom and technology, but if improperly accessed it would unleash almost unlimited destruction. Mankind attempted to access the System and failed, causing the System spread throughout space and to exert mass destruction on all forms of life, including the human race. Mankind then discovered how to properly access the knowledge and technology within the System, but could not shut its destructive expansion down because of its vast tactical systems.
Moreover, the defenses of the System are designed around destroying and overcoming entire fleets. Mankind hopes that a lone starfighter may be able to slip through and penetrate the defenses of the System, allowing such a ship to fight its way into the heart of the System and destroy it. The AFX-6502 Zanac, the most advanced starfighter ever produced, is launched on a desperate mission to fight its way to the heart of the System and shut it down.