I've played this map a bit now and I have to say, it's not as good as I expected. In the end, I recommend a half-remake of this map.
First off, the starting area, where the hell is this? I do not remember this in the movie whatsoever, why is it even in the map? It's only purpose is to give humans a slight head start by making zombies break the grate, however I feel this could be served another way that would be slightly more true to the movie.
Second, a wall opens to a building area? A wall. Opens. Why does the wall open exactly? Whatever I don't have huge complaints about it. So you run along, there's a near impossible to get on 33tick 'invisibility deagle' that naturally doesn't even work. Also there's this apartment building, once again something not from the movie and I have yet to decipher it's purpose, but I'll deal.
You make the humans run all the way around the building to a door, whilst letting the alternate entrance to the building open (which is a wall opening once again for no reason) to a kind of small crouch area that has a wall obstructing your view and naturally making it incredibly hard to shoot zombies back out into the street, instead nearly 80% of the time you shoot them at a side angle which causes them to come IN to the building. There's a soda machine to put in it in the room, but there's shit all over the ground and it has to be completely flat to fit so that almost never works, not to mention the alternate way in is already open as you enter the building and it's faster to get to than running around the building so zombies are probably already crouching their way in right when you get to it, good luck.
Humans generally lose right there, however, if they don't, they ride a elevator (Which is pretty well done, no glitching ect. ect.) while zombies have to run up stairs, at the roof they cross a ramp that's stretching across building roofs for apparently no reason whatsoever other than to be a floating ramp, there's a GMan to your right and you jump off another building's roof to land in water and proceed across a grass field to the awaiting plane.
...Wait what the fuck? This transition to the plane not only makes no sense, it MAKES NO FUCKING SENSE. This could have been infinitely been done better to introduce the plane to this map. Not to mention the random ramp across buildings, and apparently there's a random grass field behind a building/apartment area.
-------------------------
Now, BEYOND that point (assuming you even get past that point), I think the map is great the plane hold off is pretty fun, like the nades, the run to the cockpit could be a bit more extensive (make it a longer run and perhaps a box to jump over as well) but overall it's pretty good, cars in the hanger was a nice touch too.
Then Mercy does his weird Russian accent thing, begs for his mother Jesus and the plane crashes leading to the snow area, the car is really glitchy though not TOO many issues caused by it, the random snow rockfall area is alright, and the final hold off point where the ARK's are isn't that pretty or artistic but it makes sense. (except for the random train which I thought was funny so no complaints)
Only issue being that you generally make it there with zombies right on your ass which I love the thrill of that, but you also generally only make it there with a large total of MAYBE 2 people to hold off the incoming 30+ zombies in a enclosed area without much maneuvering ability. till the doors open then everyone heads towards the chain thing and I've never seen past it cause everyone dies.
-------------------------
Now for the reworking and hopefully making this into a actual movie map. First off, lets get it straight there's no way to fit an entire 2 and a half hour long movie into a map, I understand that, but having things that relate to the movie in a movie map helps a long way.
First off, the starting area. While I do not plan on giving details, a suggestion I can make is one of two. One being more practical than the other.
First: You start it in the residential and neighborhood area and have them race to a car. This can be done with hold off points at jagged gaps that break when zombies approach with cars to hold off behind, cars and objects tossed around to hamper both humans and zombies alike, while making this epic run to a vehicle. Then you begin one of the transitions like you did for the plane in the current map, fadetoblack and reopen at the airport in the movie when they meet up with Uri and his sons and that prostitute he claims to love.
Two: You start in the airport (as opposed to starting in the neighborhood and then going to the airport), you throw up some security checkpoint-like area's as hold offs, narrow doorway that slows zombies trying to get through (like a metal detector), a rope zombies have to jump over, that type of stuff as hold off ideas. Then queue the mid-way part of the map.
After holding off zombies in one of those two starter areas, you're led to the main doors of the airport leading outside where a plane awaits, throw up some bullshit console messages saying the plane is refueling and have a hold off just before the doors, have the doors open and make a run for it, zombies are stopped for a second or two and then doors open again for them, have it mainly be a straight run for the plane on open ground, causing humans to turn around and shoot while running for the cargo ramp.
Then, you continue the map as it already is.
-------------------------
Overall, I think you either make some changes to the map as it already is to improve the first points I made, or you think of something as the second section of this post and remake it to make it a more believable movie map.
Honestly, without the map name, the beginning speech and Mercy's speech, I'd have no idea what the fuck I'm playing when playing this map.