Actually, I got another one, with strange parallels to Evangelion, tl;dr if you don't care about the deepest COD lore:
COD zombies takes some context to get going, since it has 10 years worth of lore, and due to the way the story is delivered, it is really convoluted. The basic summary is that it is a series spanning 10 years, at the time the final Aether map, Tag Der Toten, was released. The mode started off very humbly, grounded even, but started escalating quickly. Long story short, there is 4 heroes, each one has the original older side(who are all batshit) and younger sides, before they lost their sanity. Thru time travel shenanigans, the younger version(primis) end up having things in their timeline go wrong, and eventually have to go forward in time to kill their older selves(ultimis). At the end of this journey, it is revealed they were never supposed to win, so instead of fading away from reality at the end of "Revelations" map, the cycle starts all over again: Every single event has to be repeated, over and over and over again, into infinity, with the same results every time, everything the player experienced up until this point was only the first cycle. This is not entirely true, however, as with each cycle, the fabric of reality slowly collapses, and things start happening differently, everything is slowly starting to get corrupted. Eventually, the characters, thru many, many cycles, regain their memory, and sign what is basically a suicide pact: In order to end their suffering, they must end all existence, and (You), the player, will help them. The process starts on map "Blood of The Dead", which ends with the primis Ritchtofen being betrayed and having his blood sucked dry, blood of the 4 being an important aspect and it being spilled serving as a metaphor. That sacrifice starts the pact of self-destruction, as Richtofen is betrayed and left forgotten and alone, dying in hellish recreation of Alcatraz as he begs his former comrades to come back for him and help him save the universe, lamenting on how he failed in his dying breaths. The very original primis Richtofen joins the crew, the one from the original cycle(being kept frozen just for this opportunity in the lab underneath Alcatraz), and together, they proceed to set the stage for the end, by retrieving the ultimis instead of killing them, as they are needed for the blood pact as well. Tag der toten is german for "Day of the dead", with the first map being called "Nacth der untoten", night of the undead, another metaphor for the longest night finally coming to an end. The very final map is a nostalgia trip, as it almost reminds the fans of everything they have been thru for the last 10 years, and reminding them that everything will soon come to a close, it is hard to describe the bittersweet feeling of playing this map, but it is similar to the NGE game, except that rather than finishing that in a span of several hours, it took zombies fans 10 years to get to the end.
The final act of the ritual isn't done by the crew, but rather by victis, a group of survivors from the very first COD universe, before it was blown up and split into infinite multiverses(it's a long story, they were frozen underneath alcatraz just like original primis richtofen), and as before in black ops 2, they are manipulated by ultimis Richtofen, the very catalyst for the universe being in chaos and disarray in the first place. As he manipulates the crew into doing the final easter egg story quest, in the background, the 8 characters(ultimus/primis) are having a feast, celebrating their "final victory"(only both richtofens and primis nikolai know what is going on, the rest are, as they have always been, disposable pawns and still think they are on a quest to save the universe). They eat and drink before their "final battle", but the wine is poisoned. The intro for the map spoils everything, the characters that zombies fans have been invested in die like animals, without dignity, still thinking there is a way out of their situation right before their final breaths are stolen away. The only one remaining is ultimis richtofen(who has become a zombie and was able to survive the poisoning) and primis nikolai, who needs to be the final sacrifice, since primis richtofen died in Alcatraz. Once ultimis richtofen finishes guiding victis thru the story quest, his part is finished, and he gets his zombie brains blown out by nikolai, a fitting end for someone who let all of this happen to begin with. The entire zombies story ends with nikolai handing over the gun to samantha(an 8 year old girl who became possessed in the original timeline and became the big bad unwittingly, but was later send thru time to disrupt events of primis and force them to start their multiverse quest, it's a long story). She pulls the trigger and ends the whole affair. The aether story ends with samantha and 8yr old richtofen(again, a very long story) walking into the great unknown, as a variation of samantha's theme plays out(originally "samantha's lullaby", now "samantha's peace"). This would be sad enough, you would think, but then you hear the 8 characters, talking about what they will do once they "save the day" from earlier as the two children walk forward. That was the part that set me off, the game really wants to get it thru to you that there was never going to be a final battle, the characters were always going to end up like this and closest thing to the ideal ending is the characters themselves describing what their ideal retirement would look like...but that's okay, because it's time to move forward and stop looking at the past. I mean that literally as you still get to control the two children, but you can only move straight ahead, signifying that this is the end of the COD universe, and the infinite cycle that was, at that point, started countless eons ago. This was actually the rebirth of the COD universe, hence why you saw Modern Warfare getting a reboot. Samantha's and Eddie's stories don't end there, and what Sam goes thru as she now has to survive in the wastelands of the entire previous multiverse that becomes later known as "Dark Aether", as an 8 year old girl, is actually pretty chilling, Sam becomes fucked up by the time she grows into an adult and becomes involved in the story of Cold War zombies reboot, then eventually sacrifices herself by the end.
Anyways, you will likely not get it if you haven't played the games, as I can hardly describe what the emotional impact of this entire final chapter felt like after 10 years of consistent story updates and rising stakes, but it was a pretty big event for COD Zombies fans. The game mode definitely doesn't get the recognition it deserves, most people think it's just rooty shooty for 12yr olds, but the entire zombies side of it is pretty indepth
So yeah, I did cry over a COD game, call me a faggot all you want but that was a pretty depressing ending. The entire final act of the game felt like putting a gun in your mouth, then pulling the trigger. Just like with NGE, the music really played an impact, Samantha's theme has major significance in the ethos of the gamemode, and I am happy that's what they used to finally close it out on