The search query "KZ Manager Millennium gameplay free" often stems from two places: morbid curiosity or historical research. However, finding a safe, playable version is difficult and fraught with risks.
It is generally considered abandonware and is not officially sold on mainstream digital storefronts like Steam or GOG due to its content.
While some niche sites like Lutris or GOG's community wishlists list the title for historical reference, it is not available for sale or legal download through any reputable gaming merchant.
Though "Millennium" was an updated version released around the year 2000 for Windows, it is not a "free-to-play" game in the modern sense.