Ultima IV: Quest of the Avatar (Atari 8-bit)

Ultima IV: Quest of the Avatar
Developer: Origin Systems Publisher: Origin Systems Platform: Atari 8-bit family Released in US: 1988 This game has anti-piracy features.

Ultima IV starts the Britannia continuity that would last for the rest of the series. It's unique among RPGs in that there's no major villain who you spend the entire game building up to defeat - your ultimate goal is basically to be a really good role model.

Anti-Piracy

The game has an unformatted track on the program disk. If it is not present, the Avatar candidate and companions will inflict minimal damage, making it practically impossible to win combat.

Although the user described a second copy protection in the game that could cause squares at the entrances to Empath Abbey and Skull of Mondain to be deep sea instead of the normal effect, this could be a symptom of the method of copying used as opposed to being the game's actual copy protection.

(Source: Wikipedia)

There are also reports that the German version allegedly used normal disks for distribution, causing the copy-protection to be tripped on legitimate copies.