There are dead monkeys in the map Ascension. There's a special round every 5 or so rounds where you have to kill monkeys. Monkeys can also be killed in the map Shangri-La.
Well the campaign is enough torture as is, but throughout the campaign there is no real signs of torture, apart from minor hints of mental torture due to the bug.
There are a few jumpscares in zombies but you have to go out of your way to look for them. In Shadows of Evil you have to have a scoped weapon and look at a very specific window on one map. So you're highly unlikely to see it unless try to. Similar in Zetsubou No Shima there's a jumpscare where you find a clone of yourself or another player that grabs you and screams. You need a scoped weapon to stare at 6 test tubes for a long while so it's also very, very unlikely you'll encounter this on accident as well.
In the zombies gamemode there's an older version of Edward Richtofen. He's driven mad by constantly hearing the voices of an ancient species in his head essentially telling him to become god and he is extremely violent and takes great pleasure in his actions.
In zombies there is a toy cymbal monkey that is used as an explosive in every map. You can choose not to pick it up. There's also a line from Dr. Richtofen in the map Ascension where he alludes to destroying toys to make his sister cry.
If you stay underwater long enough you can hear your character struggling as well as gasping for air when they break the surface. Also in zombies in Zetsubou no Shima upon running through a cloud of spores your character chokes and gags for a solid 5 or so seconds. One or more characters mentions being unable to breathe during this. Crafting and wearing a gas mask can prevent this. In Moon, if you forget to wear your spacesuit, every character has lines where they are clearly struggling along with the screen pulsing until you find air again or die.
In the map Revelations, the character Dr. Monty tells the player reality itself is being held together by "tape and bits of string" It is extremely fragmented with pieces from multiple different zombies maps all across space, and there are beasts who are trying to consume reality itself. The character Edward Richtofen occasionally gets confused as to where he is and is unsure of which timeline he's in or what he's supposed to do in it.
The character Nikolai Belinski in the zombies gamemode is an alcoholic. The younger version not so much but the older version of himself is constantly drunk and makes many, many references to drinking vodka.
In the zombies map Zetsubou no Shima, if you elect to do the Easter egg, there's a step in which you have to shoot down an American WW2 bomber plane with an AA cannon. Perk-a-colas are also periodically dropped on the map by failing aircraft. You will also see plane wreckages in Gorod Krovi, Nacht der Untoten. Those are what I can remember.
In the zombies gamemode there are lines where the characters scream in distress. In the map Verruckt there is ambience where you can hear an asylum patient screaming along with medical tools being used.
Only occurs if you choose to go into water yourself. In zombies if you choose to play Gorod Krovi, to return to the main map from Pack-a-Punch you must travel through a sewage pipe trapped in water, and in Zetsubou no Shima to turn on the power, you must swim in a flooded room for a good minute or two. There are air pockets if it helps. In the Easter Egg or to get the wonder weapon you'll have to swim through a long underwater tunnel unfortunately.
Short version for zombies: DLC3 gives you a gobblegum for "that" | Der Eisendrache Nikolai can p*ke when using wunderspheres, Dempsey will comment about nausea after wundersphere | Zetsubou no Shima, watering a plant with one of any colour can give a fruit that can make you p*ke, Nikolai when drinking a perk-a-cola can p*ke. He also has one mentioning the v word stating "there has been lots of that" when eating a gobblegum.
Campaign: At some point in the last mission (Life), someone will have to go into a chamber that has canisters of toxic gas inside. Once the door closes this character will p*ke. ==== Zombies - Gobblegum DLC3, player choice. Makes zombies do "that". ==== Zombies - Der Eisendrache: When taking a Wundersphere, Nikolai can say "This is the most fun I've had ever since-" and then he p*kes. Dempsey has three lines that mention the Wundersphere being more nauseating than the teleporter, but never actually p*kes. None of this can be avoided if attempting all achievements as two of them requires using Wunderspheres. ==== Zombies - Zetsubou No Shima: Player Character after eating a fruit activated by watering a plant in a specific order; Green, Blue, Purple. Doing this is required to get all trophies/achievements, but the p*ke lasts around 2 seconds and the character quickly recovers as if nothing happened. Visible and also audible. Zombies - Zetsubou No Shima: Nikolai after grabbing a Perk-A-Cola can say ""Eugh! You think you would get used to flavor...then it is-" he pukes and continues saying "worse than you remember!" Zombies - Zetsubou No Shima: Nikolai also has one mentioning the v word stating "there has been lots of that" when eating a gobblegum. ====