Timeline for Portal? [SPOILERS]
If the portal gun was used in the way I described, it wouldn't be much of a puzzle element. Gordon would have difficulty participating in portal puzzles since he takes impact damage. It would be more of a way of tying the two stories together.
i think that at the end of the game when glades expoleds (sorry about spelling) thats the part when that ship that was mentioned in ep2 had 'dissapier' into the the north 
For future reference, its GLaDOS
Why does everyone assume the big explosion and the dissapearence of the Borealis are linked??
The way I personally see it:
The portal gun (that Chell had) is NOT on the borealis - at the end you see land and are in the middle of a valley. there may or may not be similar technology on the Borealis though.
The dissapearence of the Borealis probably coincided with GLaDOS taking over Aperture. Possibly the last few scientists hid it from her to keep the most dangerous stuff away from her(perhaps?) or she discarded it becasue she saw no use in it.
Chell is dead - she was in a massive explosion!, leg springs or not, she's dead
The portal gun will probably remain a player controlled gun - thats even if it makes an apearence in episode 3+, which I'm sceptical about because it isn't even on the Borealis
The Borealis levels are gunna probably make me wet myself - I absolutely hate large ships and when I played through the "missing information" mod I hated being on the deck.
If the portal gun survived the explosion then it probably is damaged which will mean repairs, perhaps it is on the Borealis and you get it, only to take it to the arctic base to be repaired before use in Half life 4 (in many, many years time(episodes 1,2+3 are half life 3))
I don't believe there is any evidence Chell is dead. If anything, the final song is very indicative that she's not dead yet. Even the "dying" and "dead" lines are in future tense.
Also, I recall reading an interview or something where someone from Valve mentioned the likelihood of meeting the Portal main character in Episode 3. No, it wasn't a definitive, but I doubt they'd even mention something like that if their intention was for Chell to die at the end of the game.
The main character of Portal was GLaDOS. Chell, despite being the "narrator", was a flat character who underwent next to no character development. To assign her a personality, voice, and allegiance in the HL2 post-Combine world would be a baseless fabrication to shoe-horn her in.
I think having Aperture Science be a competitor to Black Mesa who shows up in the game is a very cool idea. It makes the world seem a little bigger. But Chell would probably best appear in passing, instead of an active and interactive character.
By that logic Gordon Freeman could be defined as a static character. I think you are missing the fact that the player experience is what defines the development of the player's character. The player's questions are the character's questions. The player's choices are the character's choices. The player's revelations are the character's revelations. Because the player goes from obedient test subject to curious and troubled test subject to rebellious loose cannon, Chell also undergoes the same development.
Yes, Gordon Freeman is a static character.
Hmm... how to explain this. Wikipedia, GO!
In some cases, such as the Myst series, the player character is given no name or defining characteristics at all, meaning that the player themselves is effectively the protagonist of the game. This is in contrast to games such as Duke Nukem 3D, where the protagonist frequently interjects comments into play, and leaves the player in little doubt as to the nature of that character, and with the impression that they are simply puppeteering a distinct and separate character, rather than inhabiting the adventure themselves.
The best way I can liken it to something is like when they make a movie out of your favorite book. And nothing is quite like you imagined it. And somehow it's not as cool as it was in your head. It would be like that. No matter how awesome Gabe Newell's vision of Gordon Freeman/Chell is, it wouldn't be as awesome to me as my personal mental conception is. Ditto, I would imagine, for you.
The Portal story has been told. It left questions and loose ends, sure, but there won't be another game that takes place inside Aperture Science labs from the point of view of a test subject. There was certainly quite a bit of implied finality on that account. Because as a player I know I'm never going to step into Chell's shoes again, I can accept a continuation of the character as long as it makes some sense in light of the events of Portal.
During the one time that I heard the portal character say something, I could have sworn it was alyx, so I would agree that it is her mom...
Retrieved from http://en.wikipedia.org/wiki/Alyx_Vance
And I can only assume that when you "heard the portal character", or Chell as she is known, you were hallucinating. Never happened.
This just in: Azian Vance at HLWiki