Your prototype looks good. I like the clean look and move away from black and gray.
The sergei logo image is cute.
The image is big, and it doesn't really show anything exciting about the game. It's just a big logo.. with a guy in it... o_O It looks more like he's trapped there, by the logo, waiting to be fragged. That's no fun.
A user visiting the site might ask himself: is there anyone working on this project.. does this project have any future? I think it's a good idea to specify in the About page who is in the OA team, and past contributors. At least it will show that you take this project seriously.. Oh, and if anybody is going to steal your work, they should know who will sue them. (joking)
It would be nice if the header shows "Latest version: 0.8.1", linked to the download page. BTW, why "files" and not "download"?
"media" is also an awkward name.. usually on the web such a page would be called "gallery".