Short review: (minor spoilers for the manga ending)
As "promotional anime shorts" for the original manga of Blame!, it's a mixed bag. Don't expect too much from these shorts. 6/10.
Pros:
+Faithful to the original manga in all its aesthetics, style and narrative coldness.
+Certain materials here are intriguing (e.g. EP3)
Cons:
- Barely comprehensible even for someone who has read but not familiar with the manga. It's more likely to confuse potential readers and intrigue them.
- Barely animated sequences are long and confusing.
- EP6 canonized one fan theory that the entire story is cyclical/hopeless, as Killy and Cibo have both gone through these events multiple times without success. (This is a minus for me, but might be a plus for some as it fits their philosophy)
If you are interested in Blame!, just read the manga, avoid these shorts and especially the Netflix movie (which is 60% against the manga's masterful atmosphere, characterization and most importantly, sheer horrifying scale).