Below is some analysis of the features, also check these links for other views:
Interesting ejecta, looking like fluid. It also implies a steady runoff after the initial impact as it is shaped by gravity being on a slope. Ejecta with force from the impact would not be.
The links in this section are not selected to promote any one theory. They are just similar formations which may imply either a natural or artificial formation.
Compare it with these:
This could be a collapsed version of the picture above.
As analyzed in the above link by Lan Fleming. Note the similarity to these: