It appears to me to be a normal impact crater with a standard peak in the center. There seems to be some darker material right below the surface, as if there is only a thin vaneer of ice on top the normal rust-colored soil.

The mars anomaly guy says "First, you should know that it is not an impact crater", but doesn't explain in detail why he says it isn't. Then he goes on to talk about flooding and dark-colored organisms and other stuff that I'm dubious can be inferred just from looking at the image, unless one has a good imagination, of course..