Background
WorldsPlayer is the name of the client that runs Worlds Chat since 1998 and is able to be run on Windows (and Linux through some additional steps). Most commonly, WorldsPlayer is found in your Worlds.com install directory as run.exe. If you elected to create a desktop shortcut, the shortcut will be called WorldsPlayer by default.
Latest versions
Version 1922
This version was created for Windows 10 and has Java built-in. It so far contains an AMD hack, Java 8 upgrade, and stability fixes. You can find the experimental client on the bottom of the Downloads page. If you have feedback on this experimental version, provide it here.
Version 1920
This version was created for Windows 7 and has Java built-in. This version was a complete update to Java 6.
Version 1900
This version was created for Windows 95, 2000, NT, and XP but requires Java 4.
For an official change-log of client versions 1877 - 1903, see here.
Version 1890
This version was created for Windows 95, 2000, NT, and XP but requires Java 3.
For an official change-log of client versions 1877 - 1903, see here.
Linux
Download and Instructions by Wirlaburla & Bad-Dude.
Old WorldsPlayer Clients
Archived WorldsPlayer Installers
For an official change-log of client versions 1400 - 1549, see here.
Non-WorldsPlayer Clients
Worlds Chat Gold
Download | Archive.org | | Press Release
The original version of Worlds Chat, Worlds Chat Gold.
Meet at Plaza (Japanese)
You can also visit a restored / converted version of this within your regular WorldsPlayer called Metap.