The game's campaign seems to be trying to introduce the Surreal Horror as seen in the original two Black Ops games that was sort of lost in the two sequels. The nature of the campaign menu and cutscenes gives off a noir vibe with its undertones of MK Ultra that provides unease to the player.
"Brick in the Wall" is a stealth mission; probably the biggest and most tense one since "All Ghillied Up". Bell has to infiltrate the apartment of one Franz Kraus while his innocent wife and son are around. Chances are, if you're coming from Modern Warfare (2019), you might especially be on your toes concerning potential civilian casualties. Thankfully, at worst, you just knock out his wife and his son cannot be seen at all; you're even equipped with a tranquilizer gun instead of your lethal equipment in case you're jumpy, but it's still a bit close for comfort.
The mission in general is actually pretty scary, as the player has to fight through a good chunk of it on their own, and in the poor lighting, it's hard to see enemies unless you tag them. As it's a stealth mission, this can become very nerve-wracking on the higher difficulties where attracting the attention of the enemy is a very bad idea.
"Redlight, Greenlight" provides its own horror, namely because you have to sneak through a base laden with soldiers, tanks and helicopters on your own. One wrong step and every gun in the base will turn on you.
"Desperate Measures" is a stealth mission, much like "Brick in the Wall", and just as tense as it. The first half of the level involves playing as Dimitri Belikov infiltrating the KGB Headquarters in the Lubyanka building. The scary part of this is being a CIA affiliate sneaking through the heart of the enemy state itself.
Lev Kravchenko continues to be as horrifying as ever as his actor Andrew Divoff's other character the Djinn, with his aggressive attitude towards Belikov. Some of his lines say it all about him:
Kravchenko:[if you choose "Kravchenko's interrogations have left me with no living suspects."] "I'm not a patient man, Belikov. Or a compassionate one." Kravchenko:[if you choose "Actually, I have a strong lead."] "Yes, and once we're finished with this mole, he'll be as blind and buriedas his namesake."
What makes the second line more horrifying as if it isn't already, is that Kravchenko already suspects Belikov to be The Mole, which makes the above an Implied Death Threat.
"Break On Through" is full of this by design. It's a massive Mind Screw (Not unlike the frozen forest sequences in the missions "Demon Within" and "Life" in Call of Duty: Black Ops III), with some Paranoia Fuel concerning whether or not Adler is someone you should trust once the truth comes out.
One of the various occurrences in the mission is the appearance of Park/Lazar (or even both of them) in the drawbridge sequence depending on who you fail to save in the previous mission. They could be seen on the bridge facing away from you. However, walking towards them will cause them to run off screen at inhuman speeds. A FridgeTearjerker explanation is that their appearance is a manifestation of Bell's Survivor's Guilt.
Aside from being somewhat of a Tear Jerker, having to kill Mason and Woods in "Ashes to Ashes" after ambushing the CIA team can be hard to watch, especially if takedowns are used on them. It can be just as bad on Park or Lazar, whom you very likely formed an attachment to.
Any which way you do it, you get a front-row seat to the deaths of Mason, Woods, Park and Lazar. If you shoot them, the killing bullet goes in slow motion and you get a lingering shot of their dead body. If you stab them, you have to go through the usual takedown animations, which is horrifying because these are people you've worked and fought alongside throughout the whole campaign.
Operation Greenlight in general. The plan itself is bad enough, putting nukes under every single major city in Europe as a failsafe against a Soviet invasion speaks volumes about how paranoid the United States is, but actually detonating those nukes? It's likely that between the radiation and the fallout, the entirety of Europe could be rendered uninhabitable forever.
And if one chooses the Downer Ending of "Ashes to Ashes", then Operation Greenlight goes off at Perseus' command and millions of people die in a nuclear cataclysm that can potentially be activated by the player themselves.
Being set in the 1980s, it'd be appropriate to mention the Nightmare Fuel-incarnate '80s films on this very topic: The Day After and, considering that the nukes are in Europe specifically, Threads. It's not hard to imagine that these movies, which wouldn't have been made in the campaign's timeline of 1981 and able to help end the Cold War as it did in real life, were a harsh reality for all of Europe, and it's all your fault.
While it's really cool to use them, the Firestarter Shotgun and Molotov Cocktails available in some missions give you a very good look at Kill It with Fire in great detail if the weapons in question score direct hits on the enemy, which can be a bit unsettling at times.
Likewise, a direct hit on an enemy (usually an enemy player in multiplayer) with any explosive will result in them turning intored chunks. Good thing you only get to see this for 5 seconds or so.
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