Previous 

To enter the game you need a Unity plug-in, which will allow you to use the browser’s 3D technology. You do not currently have this plug-in.

Recommended action.

To install the plug-in, we propose that you download the Game Client, which already contains the Unity plug-in and all the game graphics. The Client reduces your Internet traffic, and increases speed and quality

Alternative choice.

You can download and install the Unity plug-in independently. Your first entry into the game may take a little while, as the browser will load the necessary game graphics. Some browsers, in particular Firefox, requires you to reload (close all pages) to complete the Unity installation.

Download Unity for Windows.
Download Unity for Mac OS.