It's VHD (although relatively easy to make work with VirtualBox), but more importantly exe files. I don't know it cabextract or unrar can handle this. In either case, it needlessly unfriendly to non-Windows users.
That's not an official cross-platform image. I have used some tools that converts them to VirtualBox, but it hasn't been very reliable. As I said: Having official support for Linux and Mac will be great.