You'll need to play it through at least twice to catch all the story. The subtitles are kind of useful because a lot of what the prophets say can slip past you. But yeah, I feel it's only a little shorter than the original - but it's far more dense, the action is really tight, the story moves along rapidly, and it doesn't have that stretched out feeling that the original had when you were going back through the old sections in Two Betrayals and the Maw.
Yeah Turnsky, I found there was generally more humour in the whole thing actually. Have you finished the whole thing yet? I'm most intrigued by the Gravemind, myself...