Green version: you can play directly without installation. You only need to click Greening at most. You will create a shortcut on the desktop and then double-click. The advantages are convenience, no need for installation, saving a lot of time and being able to move freely in the hard disk. The disadvantage is instability, and some big games often jump out for no reason, which is very annoying.
Mirror CD: Install first. After installation, you need to insert a CD or use virtual cd. The effect is the same as that of the hard disk version, but it is not plugged in or cannot be played by virtual cd.
Other versions of the game are rare now. I think the hard disk version and the green version are the best, and the rest are basically gone now. These two are the most downloaded on the Internet.