Every filmmaker I know (who has had at least one movie get distribution) has had to turn into a sound mixer at some point because they've had to deal with splitting out DM&E's or "Dialog, Music, and Effects" tracks.
Creating DM&E's is fantastically annoying and difficult. The trick is that you have to deliver music and effects tracks which sound just like the full mix but without dialog. You'd think "Well then I just put dialog on the first four tracks in my digital audio editing program and then I run off a copy with those tracks muted and that'll create my M&E's."
You can think that, but you'll end up being surprised at just how many extraneous sounds are on those original dialog tracks. Sounds you can hear in the full English mix.
So you have to do a lot of: foley, creating new hard effects to mix on top of the sounds already there, and/or creating identical sounds and putting them on a track on your audio editing/mixing program which is muted during the roll off of the English mix and unmuted when you roll off the "M&E".
But the worst worst worst mistake you could make is to accidentally leave a piece of dialog in the M&E tracks. Because although a distributor in a non-English speaking company might forgive that the M&E tracks are missing the sound of a scrape of a shoe or a crumple of paper under the English mix, they will not be able to deal with the wrong language suddenly showing up in their dubbed version of the movie.
So today I'll be listening to the DM&E's of all of Day 2. Lucky me!
Speaking of Day 2, here's a longer trailer for a picture which is similar (The Battle of Los Angeles -- I posted a previous trailer earlier). The movie looks great. I think our picture has a better idea though, but of course I'm prejudiced.