Valve considered Portal for VR, but quickly realized it wouldn’t work

Valve's road to Half-Life: Alyx wasn't exactly straight.

While the team knew they wanted to test the waters of virtual reality technology, the Half-Life universe was not its original pick for a backdrop. Valve programmer and designer Robin Walker tells VG247 that the developer "spent a bunch of time exploring VR and talking about our various IPs."

Including Portal.

But it didn't really work.

"This is in a period of time where we’re pretty much done with The Lab. And so we’ve just spent pretty much a year building stuff in VR, we’ve got the things we’ve learned there. When we got to looking at our various IPs and asking ourselves which one of these would work well in VR, it was pretty easy to cross things off the list very quickly," says Walker of Valve's early experimenting phase of VR development.

"We felt like it didn’t make a lot of sense to do anything in multiplayer yet, the audience size isn’t there. The whole point of using an existing IP is to bring with you a bunch of work that you get to build off, instead of having to start fresh. So we looked at things like Portal, which is usually people’s first guess for what would work well in VR, and it was ours too, but as soon as we started looking at what to bring forward from Portal into VR, actually most of Portal’s later levels all rely on momentum being maintained as you go through portals."

Puzzles that rely on players maintaining momentum are harder in virtual reality, says Walker.

"A lot of them are built around that concept. We felt like that would be something that was a lot harder… There were some experiments done and some thinking done around, ‘What if you were independently controlling something through portals’, or stuff like that, but the game was getting so far away that we felt like we were losing.

Valve eventually settled on Half-Life as a better fit after creating a VR prototype using Half-Life 2 assets.

"In the end, Half-Life was the one that worked best," he continues. "There’s a set of things that are very much core components of Half-Life. The original Half-Life was built by looking at what was going on in the shooter space at the time and thinking about how there seemed to be an opportunity to do a little more than just [fighting].

"Half-Life and Half-Life 2, when we look back at those there’s a set of things we think of as the Half-Life DNA - a set of parts of that experience, in addition to combat. Things like puzzle solving and not just explicit puzzles, but navigational puzzles - you may need to find items or you may need to solve something using physics. Then there’s exploration - you'll be in an area and you need to figure out how to get out and where to go, which often leads into a puzzle or a piece of combat or something. We use a term internally called vistas, which means some sort of visual reward, narrative reward, all this sort of stuff. So Half-Life has all these pieces that we think of as the DNA and the actual experience you go through is a crafted one where we’re pulling and combining those pieces. So when we started looking at VR, one of the things we found when we put people into VR spaces in Half-Life."

"We found that a lot of those pieces of the DNA were really improved by that transition into VR. People explored a lot more and people interacted with a lot more fidelity than they’d been able to in the past. People were more careful in their movement through the world and paid more attention to everything. In the end it was sort of really obvious. By the time we’d built a 15 minute prototype - well, we built it thinking it would be about 15 minutes because it’d take 15 minutes to play through in Half-Life 2 - but people would spend 45 minutes playing through it and then really want to talk about all the other things we should be doing. It was easy to recruit internally because you’d show them the prototype and people would see it and see how they could help it and want to join."

Half-Life: Alyx released to Steam today and has so far received pretty unanimous praise from critics. We gave the game 5/5, calling it "VR's killer app". You can check out our review right here.