It’s here 
Early this morning after terrabytes of pre-loading world wide, Left 4 Dead was released to the public.
Unfortunately myself, I purchased the game before the demo….yet Steam wants me to buy it again for some reason. So I’ll have to wait for now 
We’ve uploaded all content, and as an existing customer you can switch and install to Left 4 Dead. Left 4 Dead servers are now also available for the full the game on our website at very low slot pricing.
Let’s hope the full game is as successful as the demo was.