Heyyo,
Well, if you logon to steam, it shows DOD:S and you can purchase it... but it's not out yet...
And btw, I had time to play through HL1 before then, heck, I did it more like, twice (I'm waypointing the whole SP campaign for RCbot on Sven Coop. I have just 2 levels left, 1 is incomplete and I can't seem to find cause there's soo many levels, and the 2nd I can't load yet cause of a weird problem... I'll keep trying it.
).