I did some research about that question, because I had the same one. From what I gathered:

The trailer we saw over the summer was an experimental 'prototype' if you will, that was designed to get funding for a feature length film. Although the feature length film has not panned out yet, it allowed them to make MK: Legacy.

I, for one, really enjoyed the episode, I hope that it continues to work out and blossoms into something awesome.