I can roughly split At the Gates' discography into two parts: The Red in the Sky Is Ours to Terminal Spirit Disease, and then Slaughter of the Soul onwards. What caused this division? You could say it was the departure of Alf Svensson, but it's not entirely to blame. Svensson left after recording With Fear I Kiss the Burning Darkness, and there's still some more grandiose melodies and forward thinking on Terminal Spirit Disease (although the music is noticeably more straightforward). I present this reasoning for the sudden shift in sound: this is AtG's first (and so far only) album released on Earache Records. Now most death metal bands on Earache were in shambles when At the Gates hopped on, but knowing their previous output, they could be an exception.
Slaughter of the Soul is At the Gates' 4th album, and their only album released through Earache Records. This is also their last album before their breakup in July 1996. During the initial run of AtG albums, it was normal to expect a difference in sound between each album, usually a more melodic sound than the last. This album, however, is likely their most "thrashy" album of theirs. This isn't an unusual change (The Crown would go through a similar process a couple of years later), but it is something to note when coming in. This isn't any noticeably more accessible than Terminal Spirit Disease (which to be fair is very hard to do while still being death metal), at least in riffage. As for the contents of the album, well...
This album isn't irredeemable by any means. There are genuinely good songs here. But for the most part, Slaughter of the Soul is a textbook example of shite mallcore that prioritizes itself on appealing to people that never grew out of their daddy issues more than actually making interesting music. Every single one of its ideas was already either done better on Terminal Spirit Disease or would be done better by bands like The Black Dahlia Murder or Darkest Hour. Even if this album wasn't outclassed by what would eventually come, the previously superb riffage that would define past AtG albums is gone, replaced with watered-down chugging with interspersed "melodies" that bring about more of a Machine Head or even Slipknot vibe. It somehow drags in the 35 minutes it's given thanks to the hilariously low concentration of ideas on display here. There are 9 actual songs totaling 30 minutes of runtime, and you've heard every idea the album has to offer by the end of the second track. It's probably the single steepest drop-off in metal without any one explicable cause. At the Gates went from making master-class death metal to...this.
Some tracks do manage to escape the unyielding criticism I would have otherwise given this album. "Under a Serpent Sun" is probably the best song on the record, and along with "Suicide Nation" I would consider are the only songs that are better than anything At the Gates did beforehand. The rest ranges from almost tolerable ("Blinded by Fear", "Nausea") to complete hogshit ("Cold", "Unto Others", "Need"). The tracks are all stone-stupid ordeals that are played more mechanically than any dime-a-dozen tech-death band with zero emotion or life pumped in, playing away hopelessly on the border of accessible and aggressive without committing to either side (fans of latter-era Death should be familiar with this) and ending up all the worse for it. All the riffs follow a basic template of Open B chugging followed by some basic sugary-sweet Gothenburg melody. All of the songs are verse-chorus. All of the choruses on the album are huge and easy to sing along to, which wouldn't be a bad thing if they were executed with any skill or conviction. Any break from the chugging is a little widdly-woo solo that is a waste of talent from the guitarist playing it. The interludes suck too, they don't pass the "if it was the entire album, would I like it" test and they're downright pretentious in their execution. So what separates the two songs I mentioned above from the rest? "Under a Serpent Sun" has a cool intro and outro with a nice riff buried in the chug, but I honestly could not tell you for "Suicide Nation". Maybe there's a slightly looser/groovier feel, more of a contrast between sections. That song also probably has the best non-guest solo on the album, so that's also a factor.
This is about as close as death metal can come to selling out...without actually selling out. The instrumentals hold about zero actual death metal in them, which is not necessarily a bad thing. If Tomas Lindberg did all cleans here, people would probably hail this as Reign in Blood 2. While that would make the album better (Lindberg's vocal performance is fucking dreadful here), it still doesn't fix the core issues of the album, being the boring and samey nature of everything. Every riff on the album can be swapped out for another riff. There's a section in the middle of "Unto Others" that can be plopped literally anywhere in the album and it would have fit. The same goes for "World of Lies". Same for the title track, and "Need", and every other track on the album. You couldn't have done this with past AtG albums. It's so interchangeable and lifeless.
It doesn't help that the production suuuuuuuuuucks. This may be some of the worst production ever put to tape in heavy metal, there's about zero low end to everything and all of the rough edges have been smoothed over. Every performance, every aspect of this is "studio perfect". It's soulless. It's actually grating in its over-sanitation: guitars buzzing like a half-broken pair of dollar store earbuds, drum tracks triggered and quantized more than a Fear Factory album, bass tracks that might as well not exist, and Lindberg's obnoxious vocals dominating the mix. And of course, the entire thing is brickwalled to shit.
What do people see in this? Where is the vaunted melody? Where is the aggression? Where is the metal classic that everyone should listen to? And most importantly: How the fuck did the Björler brothers lose their god-given talent so quickly? And it's not like they would produce nothing but shit from then on, they'd form The Haunted after AtG disbanded and they would continue making great metal. This one-off turd is completely unexplainable in the otherwise flawless run that the Björler brothers had up to and including Revolver. Slaughter of the Soul has no riffs, no soul, no conviction of any kind. It just exists and is "catchy", so people like it.
If you enjoy low-quality riffage with edgy lyrics that you can blast in your room whenever you feel sad or angry (see also: Slipknot), this should be right up your alley. Those of us with taste, stick with anything else these guys did.