Word Of God says they take place in the same universe, and both have direct references to each other. From what the Fandom has gathered, Half-Life Episode 3 / Half-Life 3 / Portal 3 will center around the Borealis, a plot device in both stories.

On the other hand, they are still separate games.

If a fic is about Gordon and the gang meeting up with Chell and the motely Aperture Science crew, is it a Crossover, or... what?

It's not a crossover, but it is pretty stupid, as the games do not indicate that they will be going in the direction. (Yes, Aperture will be important in the next Half-Life game, if it comes out, but the Borealis is nowhere near the facility Chell was just released from.)

No.

Not at all.

Portal 2 did put some distance between the two, but everything that's canon in one is also canon in the other.

However, the two are so different in tone that it would probably be written as if it were a crossover, what with the irreverent humor of Portal not really working too well considering the looming war that threatens to wipe out all of mankind.

I mean, just imagine Wheatley meeting Dr. Breen. It'd be hilarious, but at the expense of the weight of Half Life's storyline. Breen is a dictator who not only allowed but encouraged the Combine to to be enslave, sterilize, and mold humanity into something unnatural. Wheatley might as well meet Hitler.

I'm not discouraging the idea of merging the two storylines, just saying how it should be approached. Care is needed to keep Half Life an action series and Portal a comedy series. They can be compared to being universe A and universe B because they're genre A and genre B. Not technically, but from a writing standpoint.

edited 2nd Mar '12 12:17:16 AM by SgtHydra

They take place in the same universe but their stories travel in different directions.

My answer would be yes and no.

It's still a crossover. It's an Intercontinuity Crossover.