The writer behind the Half-Life series, Marc Laidlaw, has revealed some details about why the franchise crossed over with Portal.. Half-Life is one of the most beloved gaming franchises out there. It's known for some incredibly innovative and creative gameplay with a super original, mind-bending story that goes all across space and time. It's a fascinating series... and it has almost completely disappeared from the zeitgeist over the last decade or so. Strangely, a very similar thing happened to the Portal series which shares a universe with Half-Life. Fans expected the two to cross over more aggressively when the Borealis ship was discovered in Portal 2, but that was the last major thing anyone ever saw that linked the two franchises.