Not any shorter than advertised, but I don't think I realized how fast 5
or so hours can go by while gaming.  There's definitely some replay
possibilities, I missed a lot of stuff, there's a stats function that's
fairly comprehensive and I'd like to improve my first go through
results.  Embarrassing.  The game is pretty hard, I've often found
myself at difficult junctures, with a bunch of enemies to face and
around 15 health.  That's either hard or annoying, I'm so used to games
giving you an opportunity to completely gear up before going into a big
firefight.
The first episode wasn't quite a blockbuster, but I was left wanting
more.  The original SiN was so completely imbued with the characters of
John Blade and his annoying sidekick JC, that I missed hearing their
voices all the time in Emergence.  John Blade has become much more
Gordon Freeman and much less Duke Nukem.  Unfortunately SE:E is running
off an old (Feb 2005) Source build, so there are stuttering problems
when loading and no HDR.  Hopefully that will be rectified.

It was still well worth the $17.95, and I'll be buying the next
episode.  I guess now it's time to hit my credit card for another $17.95
for HL Episode 1.