Well, Valve has started to link the story of Aperture Science in with Half-Life from what's happening near the end of Episode 2. In fact, we find out that the tanker you're going to be looking for suddenly disappeared so it could mean that it has some sort of portal technology on that.
While not official, somebody has tweaked the game to add the portal gun in Half-Life 2 (I think the video was showing it in Episode 1). However, the AI really had no idea what was going on, but it was cool when the guy used portals to get around.







