Fire Dunes is a wide open CTF arena. It is very good for attacking your opponents in the air and by ground. Each base is fortified with many walls, but there is many ways to get in. Be sure to watch your back from every angle in this desert level.
You may have also noticed the new sky. All the levels in Silas have had their skies re-done so it looks much better. As well, all the lighting has been revamped. Another a side note of interest - Fire Dunes is the brightest level in Silas. It's good to let the sun shine now and then. :)