A Half-Life spin-off called Ravenholm was once in the works at Arkane Studios, which if you've kept up with the leaks over the years, you probably already knew that.
A new documentary from Noclip called The Untold History of Arkane has been released and in it the Dishonored developer discusses its projects over the years, including the canceled Half-Life spin-off, Ravenholm.
Back in 2016, Warren Spector and his team at Junction Point were working on a new Half-Life 2 episode. The studio never finished the game, but the prototype was handed over to Arkane Studios when the development studio was hired by Valve to create what was called Ravenholm.
One of the cool things included in the episode, and created by Junction Point, was a Magnet Gun, which was freeform in its use, and would attract items like a gravity gun. You could fire spheres, magnetize objects, and combine.
The team at Arkane quickly had a build and started working on a script where the action was taking place around Ravenholm.
In the game, you would have played as Lieutenant Shephard from Opposing Force, and met up with a fellow by the name of Father Gregory who took refuge in an asylum that acted as an experimentation center. The building at one time in its life featured a children's hospital, so you would have found toys on the floor of the place, making it "a bit creepy."
Arkane goes on to talk about the game's leaks, once of which occurred back in 2013. Many were touting it as Half-Life 3 or a new episode, but Arkane didn't consider it a new episode. It had Half-Life Episodes 1 and 2 in its build, because the team was working with Valve, which is why they had the code.
But Ravenholm was really a standalone spin-off in Arkane's eyes, and whether Valve considered it an episode or not isn't known, because the game never saw the light of day.
If you click on the 33:33 mark in the video below, you can hear Arkane discuss Ravenholm for yourself and get a look at some footage.