I don't think it would work as that, either. The Killing Joke's backstory for the Joker was never intended to be definitive (read the Foreword). That they took it and canonised it shows only that they misunderstood the book's intentions.
Absinthe's post is very insightful. Drawing on the recollections of the first experience of playing is surely the best (and only?) way to go about re-creating the original in Source.
How did the developers manage to overlook the fact that in the very dialogue in question the marines are shown...
If they are going to go with the exact same intonations of speech as the original voice-overs, why replace them? The track is good. It's exciting. But it's out of place in the video's set-piece. It's jarring - two different things are trying to assert themselves, the game and the music.