http://www.cnet.com.au/games/print.htm?TYPE=story&AT=40057064-39029232t-10000120cKojima gave some information on MGS4's enemies as well. The mechs that are seen walking together with soldiers and tanks in the trailer are a new type of Metal Gear called Gekkou, which means "moonlight" in Japanese. They're a mixture of mech and creature; the upper half of their body is mechanical, but their legs are organic.