The first thing I noticed about Wrathprayer compared to other black/death bands they're supposedly similar to, is that Wrathprayer actually have songwriting abilities. Their riffs flow from one to another smoothly, the band's transitions maintain momentum expertly without droning on and on. Musically I don't really think there is much black metal happening on this album, for better or worse it's death metal with a few conventions borrowed from black metal, particularly in terms of the atmosphere, vocals and production.
The production is rather good considering what the band was after, you have the cavernous depth and salted guitar tone needed for a black/death metal type sound, but the angularity and dynamics of the guitars are preserved so that the riffs are easily distinguishable from one another, unlike the type of production you'd find on a more classic black/death album like, oh I don't know, Fallen Angel of Doom. For this reason I expect the production on The Sun of Moloch to be a dividing point. If you're really a fan of the production jobs on the typical "war metal" albums you'll probably find The Sun of Moloch to sound way too clean, whereas if you listen to primarily death metal you'll count the production job as a positive aspect of the album.
When you start looking underneath the layers of production, you'll find that Wrathprayer's music draws a lot of influence from bands like Incantation. The riffs are primarily tremolo spam and they aren't shy of using pinch harmonics, but they avoid monotony with a lot of clever transitions and variation from the drumkit which when done correctly, as it is done here, can make the same riff sound completely different with a different rhythm driving it on the kit. The riffs themselves sound a lot like something Incantation or Immolation might write, banking on mostly diminished and augmented intervals with intelligent chromaticism. The production job makes it sound like these songs are emanating from a steadily splitting fissure in the earth rather than being up in your face directly, but ultimately my point is that if you gave this album a Dead Congregation-like production it'd still sound awesome in a completely different way. There is real worthwhile musical substance here, something black/death, especially the kind NWN seems to commonly stock, often lacks.
Despite the quality of Wrathprayer's debut album, there are a few points to find fault with. First is the production of the drums - I don't mean to say they are poorly produced, but I would've liked to hear a more cavernous reverb or distorted sound on the skins (snare, toms) as opposed to their rather thin sound on the record. Secondly is the presence of the intro and outro atmospheric soundbytes, which I'm just personally not a fan of in death metal or black metal. The "Prayer" tracks that open and close the album are good, but the abbreviated clips that open and close a few tracks have never appealed to me, no matter which band tries it. Usually it just strikes me as a cheap way to convey an atmosphere the band can't achieve with their instruments. I'd rather have such external clips worked into songs on a more synergistic or macroscopic scale.
Lastly, and the greatest reason I'm giving this album an A instead of an A+, is that as good as The Sun of Moloch is, it's pretty derivative and isn't really a groundbreaking album in my eyes. Everything Wrathprayer does here, they do well, but they're doing things have been done before by plenty of bands before them. In terms of new old school metal, innovation isn't really the focus though, it's doing the same thing the bands of the past did, but better, whether that means a new combination of old school influences, better musicianship or a superior modern production that brings out the best elements of the genre we couldn't hear on the older records. Wrathprayer succeeds in all of those respects to a certain degree. Highly recommended if you are a fan of the blackened death metal style, or even a fan of old school death metal with a casual interest in the black/death scenes of South America (or Canada for that matter).