Well, honestly I haven't learned every detail of the game as of yet, but I've been able to beat petra on a variety of maps.
I also neglected to add links to all of the things that I mentioned previously, which I should correct.
Zero-K
Spring RTS Engine
Zero-K Graph Based AI (does not cheat)
Shine 2D, an openGL (fixed pipeline, because reasons) 2D graphics library for java
Some things I would like to see implemented for 0AD:
-Make refractive water less derpy and balance reflections/refractions to make water look more like water.
-Dynamic clouds (with map settings)
-Dynamic sun/moon with day/night cycles and color points for e.g. sunsets and sunrises, etc.
-Precipitation, with related cloud settings (although not necessarily having the precipitation come from clouds, just changing their appearance during)
There are plenty of other minor things (and a few major ones) that could be tuned or improved either to improve performance or improve the aesthetics and increase the sense of realism, but I don't really want to get ahead of myself.
I don't really want to touch gameplay or balance for as long as humanly possible, although I may offer suggestions from time to time. I'm not fundamentally opposed to doing AI/unit AI type of work (and 0AD could certainly use it), but I am a bit burned out on that.