During development, Valve actually decided to include a way to play Half-Life: Alyx without the need of a virtual reality headset. The developer-only mode was meant to fasten the development of the next chapter in the Half-Life franchise by allowing the developers to freely move around the environment at will.
The debug mode was then shipped — maybe accidentally — when Half-Life: Alyx launched a couple of days back. Valve has since then patched the non-virtual-reality mode out of the game. However, modders and dataminers have already unearthed a set of launch parameters and console commands to get that mode up and running. In other words, Half-Life: Alyx is already being played out there with traditional peripherals rather than bulky virtual reality headsets.
Speaking with Polygon in a recent interview, co-developer Robin Walker stated that modders will eventually create a non-virtual-reality mod for Half-Life: Alyx. However, that will not be something good because, as Valve fully knows, the game was designed from a virtual reality perspective. Removing that core pillar will make the game feel just wrong.
I’m fine with it, for the sake of the other members of the team I don’t want to say I encourage you to do it, but it’s going to happen. I think people will then hopefully have an even greater understanding of why we decided to build the product in VR than they do now.
Walker previously stated that Half-Life: Alyx pushes the main story forward despite being a prequel. The narrative and content were both prioritized to be “relative” to the rest of the installments that have released so far. Hence, Half-Life: Alyx has an important part to play overall since the game serves as another piece of the puzzle. He advised all fans to play Half-Life: Episode 2 before donning a virtual reality headset for the new entry.
Episode 2 was the last installment to release in 2007 before the franchise was seemingly shelved by Valve. At the end of that storyline, Alyx lost her father Eli as she escaped with Gordon to find Dr. Mossman. Her follow-up to the loss was never revealed since Episode 3 — Half-Life 3 — never saw the light of day. While Walker refrained from mentioning if Half-Life: Alyx would somehow bring closure to the missing episode, he did suggest that playing Episode 2 beforehand would be a good idea.