I've never said it I don't think. But this story is meant to be an alternate universe to Half Life where the events happened differently. However it's been confirmed that Half Life and Portal are in the same universe, so why wouldn't it exist in my story as well? Mentioning that. I'm considering including Portal characters.
So far I only have a basic idea where Y/N stumbles across the facility by accident and essentially goes through the game's events. With a few minor differences and Glados joining the war by the end.
Speaking of concepts for Glados, here.