There is a story here; a story about how awesome (yes, awesome) and ruthless the space marines are.
It functions great in the last part as cosmic (Lovecraftian) horror. The rest of the parts are just a thrill ride of incredible directing, animation, cinematography, sound design, action, and style.
The only problem is that the first parts are slightly worse when comparing to the last one as they are really short and their art/animation quality is a bit less detailed. There are a lot of dark shots where, when you are watching for the first time, you might not know what is exactly happening.
Also, this is clearly for the fans of the 40k universe, thus someone who is going into this completely blind probably won't understand a thing, but they will enjoy it nonetheless.
Review of Astartes
