I know this is nothing revelatory to say of the first book in a 50-something volume series, but it felt like it was just the start of a bigger story, without a lot of resolution. Which is fine, and I guess I expected.

Having NO prior knowledge of the Warhammer 40k universe, I felt like a lot was going over my head. Don't get me wrong, it's not that I didn't like the story, I just felt that a lot of it was referencing things the significance of which I wasn't aware of.

I've read that the first 3-5 stories should be read together as one arc. They're cheap and short enough that I will probably get the second one at some point soon.