This one has a whole lot of cool stuff in it, and you should totally check out the release notes. I'd tell you more about it, but I-am-so-exhausted.
The brief version: massive performance boost on ATI in particular; control scheme improvements for non keyboard+mouse players; miscellaneous fixes; less insanely difficult battlefields.
More to come soon. Enjoy!
This is a standard update that you can download through the
in-game updater itself, if you already have 0.500 or later. When you
launch the game, you'll see the notice of the update having been found
if you're connected to the Internet at the time. If you don't have 0.500 or later, you can download that here.