ASD - Tower Defense is an open-source Tower Defense game developed in Java.
Current version : 2.0 beta4 (Nov 2010)
The main site is here: ASD HomePage
(This site on GitHub is a Backup Page from code.google.com/p/asd-tower-defense)
Why this Tower defense is different than others ?
There are a large number of "Tower Defense" games but in most of them, creatures move on a fixed path. In this game there is no predefined path, you must slow the creatures strategically to prevent them from reaching your castle. To achieve this, the player can place the towers on the ground to force the creatures to move in another path. Thus the player can determine the path that the creatures will follow.