As for Ep3 itself - this is Valve we are talking abut, they are legendarily slow with these things. I would guess that at the moment, the Ep3 source code looks something like this:
Code:
//HL2 EP3
//game goes here, eventually
/*
* TODO: Write game
*/
Quite true there.
Ah well, at least you can rely on Valve to come out with good games.