Heres my little theory on this ending and what it means for the story (this is a long read so be warned!) *Also sorry in advance for my terrible grammar, it's late and I'm tired*:
The whole Zombies story is made up by Sam and Eddie. It's just them playing with action figures on a crude play mat/set. This would explain how we jumped from map to map. Whenever we got a new map it was because they got bored of that map and played with another one.
I would also like to point out that if you try and say that this is the cutscene before everything in zombies happens you couldn't be more WRONG. We can clearly the action figures of the N4.
Eye color
We all know the reason that the zombies eye's change color, it's because Eddie (Richtofen) has gained control, both in the "made up" world and the "real" world.
Sam had control for BO1 (W@W maps are a part of BO1 btw), and Eddie had control in BO2.
As for eye color in the "Origins" map Sam and Eddie argue on what the eye color should be so that's why you see both.
Sam's room is the Aether!!
In BO1 you know that Richtofen wanted to control the zombies, to do this he had to go to the Aether.
(Before I get any further on explaining why Sam's room is the "Aether" I'd like to explain that Eddie is "playing the game" as Richtofen)
So to do this he had to switch "bodies" (switching bodies in-game is a metaphor, he does not actually switch bodies) with Sam. This would take him out of the "game" and put him in the "Aether" (Sam's room), and put Sam in "the game".
This would mean that he now has control over the zombies (makes up the rules of the game) and that Sam has taken his place in "the game".
So in short the "Aether" is a metaphor for Sam's room.
Sam is playing in the game?!
Here's where my theory still needs a bit of polish. When Sam is "playing the game" (see above for reasons why) she needed/wanted to make up her own set of characters. (She also has Richtofen as her character now too, but she likely wanted to make her own "new" storyline set in the same universe) She made the N4 as her group and she most likely plays as Misty.
Maxis and the game, + relations with Eddie
Maxis may also take part in the game from time to time. (He tell's Sams' group what to do, and during his ending he "ends" the game altogether meaning that he may dislike Eddie hanging out with his daughter [Richtofen seems to dislike Maxis VERY much this may be a reflection on how Eddie really feels about Maxis] or he [Maxis] may just not want the two playing such a silly game anymore) Either way Maxis has some influence on the game.
Ending was planned, + map/gun inspiration for Eddie and Sam
If you have ever played Kino then you know that when you teleport you have a chance of entering Sams' room during one of your teleports. In this room you will find the EXACT same layout as in the cutscene, some posters on the wall, but most importantly you will see that in fact on the floor is a set of O4 action figures and a makeshift "real" version of Der Riese. This was a HUGE hint from Treyarch as to what was really going on. (To explain why in the cutscene she has more posters, Treyarch may have known how they wanted to end it, but they didn't know the road that would lead them there,
Sam and Eddie take a lot of what they see in the comic book and and implement it into zombies. A lot of the BO1 maps came from the comic book and a lot of the weapons as well. I.E. every map with playable O4 has a comic book page as a loading screen and if you look at the Moon loading screen you can see a whole slew of weapons used in various zombie maps.
Hellhounds came from Fluffy, as he/she would often interrupt their play sessions by coming in and trying to chew on the action figures etc. (Represented in-game by Hellhounds occasionally coming to try and kill you)
Cutscene setting and why maps can be in the "future"
The cutscene most likely takes place during the Cold War.
It was not unusual for sirens to go off as a practice (nuclear threat was HUGE back then)
The pajamas are definitely not WW1 era stuff.
Posters are not WW1 era stuff.
The Tranzit bus is clearly of modern design and is a toy in Sams' room.
The action figures are not of WW1 either.
The map "Five"
The map "Moon"
The map "Ascension"
For these reasons (and more) the most logical time frame for the cut scene is the Cold War era.
This would mean that Eddie and Sam would still be alive when the 2000's rolled around and able to play on maps that take place in the "future".
Sam and Eddie possible love interest?? and what the break in maps represent
*This paragraph could be considered fan fiction*
So if you watched the ending then you would know that Eddie is probably not Sams' brother. (He says something along the lines of "Come on, we'd better do what your dad says..." why would he use "your dad" if he wasn't related? If they were brother and sister you would think he would use just plain old "Dad") This doesn't leave out the possibility that they could be cousins, this can lead us 3 ways.
1. Sam and Eddie like like each other and possibly become life partners
or
2. Sam and Eddie are cousins and Eddie is spending the night over his cousins house
finally
3. Sam and Eddie are very close friends and Eddie is spending the night at Sams'
For all intents and purposes I will just stick with possibility #3.
The breaks in maps obviously (in real real life) means that Treyarch is (during a break in dlc) working on the next dlc, or (in a break in-between games) Treyarch is working on the next game while the current IW game is out. But what does this mean story-wise?
The small breaks (dlc) mean that Sam and Eddie have taken a break for maybe a day, week, hour even, from playing the game in their world, (in our world this would mean a 1 month break).
The big break means that they have taken a significant amount of time off from the game i.e. at least 7-8 years.(1 yearish in our time) This ties in with a lot of what I said earlier.
Now after such a long break from a game, you would assume that they forget about it or something but I don't think they did/will. They have a spent a lot of time playing the game as seen by how many maps there are, so I think they really love playing it.
Now with Sam and Eddie being such close friends you think they would keep in contact over the years and occasionally meet to catch up on things and etc. This is when the they would begin to play the game again (i.e. BO1 gap to BO2, but they have changed the rules slightly i.e. buildables, perma perks, double upgrading, etc.)
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And that's basically what I think the cut scene means for the story.
I realize this ending may be very disappointing to some and maybe even made some quit zombies, not me, I still want to know what happened to the O4 on Moon and the N4 at Buried, even if it is a story created by children.
