So we know a little about the beginning...now let's speculate!

[Tamora]

While it would make the whole "last thing you remember" thing make sense. How could someone be removed from the past yet still have a complete history in the future. Paradox. Not likely. (IMHO)

Good point there jason But that's the whole deal with timetraveling right? So, if there's timetravel in HL, it would all make sense. Not that traveling through time do make sense in real life though hehe

 

[EVIL]

I think that right after the conversation with the g-man he got drugged or some sort, maby some venom that will let him go into a come untill you give him an antidote, maby g-main did this just to get him out off his way while he shapes the world by letting the combine taking over earth

 

[EVIL]

and the maps arent stricktly e3 maps.. i am sure you will have the seabed fight sequence in the final game, also the prison because the prison is confirmed to be in the final game!