The new shader-based renderer mode in 0 A.D. Alpha 5 is designed to support new effects while improving the graphics rendering performance. There's also improved lighting for warmer and more vivid colors, new particles, terrain decals, hidden units, and various graphics performance improvements.
In terms of game-play updates with this newest release, there's a new "Iberians" civilization, improved enemy AI, random map scripting, unit promotions, improved formations, and a new map.
Also falling into this update for Windows / Linux / Mac OS X gamers is improved user-interface functions, artwork, and new audio (sound effects and music).
The latest build of Wildfire Games 0 A.D. is available for free download from the project web-site.