For fans of B5 it's fun to see all of the interesting alternate realities and see old characters again, but the story doesn't make all that much sense and the dialogue is kind of forced a lot of the time. They just jump around a few hypothetical realities with no real rhyme or reason (for most of them, anyways) and eventually the movie decides it's time to stop. The movie has more flashbacks than are necessary, maybe just to pad out the runtime a little bit, since this is a pretty short movie at around 75 minutes.
The updated, higher-fidelity models for shadows, their ships, etc are very cool to see, although the animation falls flat sometimes.
At the end of the day it doesn't add a whole lot to the B5 mythos apart from exploring some alternate realities which were alluded to in the series and potentially setting up a reboot, but it's fun enough to rent for fans of the series.