Ironclad: Steam Legions is a steampunk strategy game with an AI opponent. It lets you pit your strategic skills with battle tanks, infantry, artillery, and warships against a fast thinking enemy in a hex-based battle arena. It is still under development in the alpha phase. However, the game is fully playable, with a complete set of tutorial levels to master, with sound effects.
0 A.D. (pronounced "zero ey-dee") is a cross-platform real-time strategy (RTS) game of ancient warfare. It's a historically-based war/economy game that allows players to relive or rewrite the history of ancient civilizations, each depicted at their peak of economic growth and military prowess.
Liquid War 6 is an original multiplayer wargame. You have to control an army formed with thousands of pixels that look like liquid, and try and eat your opponent. This is a total rewrite of the (now quite old) Liquid War 5 version. It's still in beta stage, with many imperfections and no network play but it's playable now.
The aim of this project is to create a free (open source, OS independent) remake of the classic SSI game Imperialism. While the spirit and many concepts of the original should be preserved, it should not become a pure copy but advance the concept in a sense that modern elements of strategic games are included, e.g. of the Civilization series. The game is written in Java using Swing for the user interface. The philosophy is to keep it as simple as possible, use standard/well tested libraries wherever possible and to demand clean, understandable code.