Being a former guitar player, I would say that the songwriting is decent and in some respects a little bit more in unison with the keys that did drown out the guitars on earlier releases, namely "Hate Crew Deathroll". That album is a classic, but a lot of the songs stressed more of what was done mixing in the keys too much, which did overshadow the guitars on some songs, just not on this one. Like I mentioned, everything blended in casually and Alexi again flared his playing with a lot of influences, especially Mozart, when it came to writing the riffs and leads reflecting (to me) that of the works of the legend Joe Satriani.
This release is more of a melodic death-type of album instead of a melodic death/power metal album. It's filled with relentless energy and emotion, sort of like that of the Amott brothers during Arch Enemy's earlier days, just not as heavy and brutal as those first 3 releases of AE's. Alexi is still powered up on vocals, spewing out hatred and furious vox that keeps the music really aggressive. The clean tone segments were few here and not many instances where they are featured song-wise. Pretty much most of the songs are highly musical and actually worth hearing many times without lessening in outward disinterest.
Alexi (I think) has gone through peaks and valleys when it comes to previous releases, knowing that on some albums they are kind of just "crowd pleasers" rather than original pieces of melodic death/power metal that COB demonstrated on "Restless, Relentless, Forever" and "Are You Dead Yet". With "Halo of Blood", it is more intriguing to listen to, plus as I've already said the production quality has made this album a much higher quality release than these previous other releases. Their hatred is still rampant even though (to me) it isn't their most innovative piece of material.
I'd admit to say that when I originally heard this, I was really upset with the lack of ingenuity factor, but after repeated listens I'd say that COB is still kicking ass. The lineup is pretty much the same as their previous ones and the backup vocals really augment the hate-spewed aggression that really stands out on this one. Get ready for some heavy duty blast beats as well with super tremolo-picked guitar melodies! I have yet to hear many bands that are melodic death/power metal, so (to me) it was surprising. A definite step up from their previous 2 releases and definitely a good one to buy and keep in your COB collection!