Hmmm. "Aftermath" was a done deal for me, a "purchase the first day it comes out" kind of game. However, that was when it was a full-featured expansion and the quoted price over Steam was $12.99.
Somehow, 4-6 hours sounds pretty anemic after having almost 18 months to work on the expansion, and $19.99?
Now I'm waiting for the reviews. I liked Half-Life 2, but I'm concerned over the way that Valve seems to really be milking the franchise for every last penny. If the reviews are good and I'll get more than 4-6 hours of gameplay (I tend to take my time and explore), cool.
But i can also walk away from this one if it's just mediocre &/or if it really is just 4-6 hours when you take your time. Voting with our wallets is the only thing that gets through, and I have plenty of other great games to catch up with if I miss this one.