There are a few things you need to know about this score. First off, Zimmer composed it "blind", essentially being made to work off the script, and not the finished film. This makes it an unpredictable and utterly separate work, with different pacing to the film.
He also hunted down a French sound-engineer to digitally rip out the opening trumpets from Je Ne Regrette Rien and wove it into the opening Foghorn style attacks. Slow down the Edith Piaf original and you'll hear it's the same.
Why did he do this? Well, since time stretches in a dream, so does the music. Remarkable.
Also brilliant is the track Mombassa, which has an unusual moment around 3/4 in where the brass section blast out 3 notes, all exactly an octave apart - a very unusual and uncommon moment in music. Again, it seems Zimmer may be pointing to 3 "levels" or planes within the music - of course if you compare the music to that point in the film, this "3 level" note makes perfect sense.
A wonderful, intelligent and ass-kicking album. GET IT.