I agree that the first episode was the weaker of the two. I think the underlying premise was fascinating, but it was--even for JMS

--too verbose.
I also would have preferred if they'd touched more on the "Is it really a demon or is it an alien?" question. B5 was always really good about leaving both possibilities open; this one seemed to come down pretty hard on the "it's actually theological/supernatural" issue.
OTOH, I'd love to see the plotline come up again in future installments, where perhaps they can get into just that.
The second episode, I thought, was almost quintessential B5. I love the fact that, 10 years later, Bruce Boxleitner is still Sheridan. There was no disconnect, no nothing; it really was like stepping back in time, vis-a-vis the character.
My only complaint about the second one is that I'd have liked more of the original cast involved. One of the best thing about B5 always was the way the characters interacted with and influenced each other. I'm afraid that, in a series of vignettes that only focuses on one at a time, we're going to lose that.
Oh, I was really moved by the G'kar voiceover at the start. I miss Andres Katsulas.

(And Richard Biggs, though I admit not as much.) And the memorials to them--both in the episode itself, and in the special features--were also really touching.
Overall, not a home run, but definitely at least a base hit, and I'll be getting future installments if/when they're released.