The first Half-Life game in 13 years might prove to be the first killer app for VR. In the 23 days since Valve announced Half-Life: Alyx, its first full-length VR game, the company’s Valve Index headset has continually been number one on Steam’s top sellers list — until yesterday, when another VR game called Boneworks surpassed it.

Even though Alyx may be pushing some to spend serious money on VR, the company tells The Verge that it’ll be a traditional Half-Life game in some key ways: it’ll be a linear adventure from start to finish, one that’ll let you save the game whenever you’d like. Valve also suggests that you’ll be able to play it for hours on end — even though you’ll be wearing a headset that’s physically tethered to a computer.

“Today, we generally see playtesters go for 2-3 hours before taking a bathroom break,” programmer Robin Walker told The Verge over email. While the team originally designed the game to be played in shorter bursts, Valve saw that players’ first reactions would often be “Wow, that was the longest I’ve ever been in VR,” and they wound up playing it for longer.

Don’t expect deathmatch

That’s an impressive claim, and it may depend heavily on which headset you use. Alyx supports a lot of them, and experience has shown us that not all VR headsets are equally comfortable. Walker says small things like the fact that you don’t have to constantly grip the Valve Index’s controllers to hold them (since they’re strapped to your hands wrists ) can make a difference.

There is one other way that Half-Life sadly won’t be a flagship release in the Valve series, though: Walker tells us that, unlike Half-Life and Half-Life 2, there’s currently no deathmatch or other multiplayer modes in the works.

(If you want to play Valve VR games with friends, we do hear a credible rumor that Valve’s second full-length VR game may be Left 4 Dead VR.)

Since Valve is a company that doesn’t tend to say a whole lot publicly, we’re going to print the full set of answers to our questions from Walker below — including additional intriguing tidbits like how the trailer you saw is composed of actual gameplay and how Valve’s working on accessibility options for Alyx. You won’t necessarily need to stand up, walk around, or swing the controllers to experience it.

How true to life is this trailer? We spotted Jane’s tweet, but want to confirm: is this a representation of what it’s like to play the game, or actual gameplay in motion?

Robin Walker: All the scenes in the trailer were recorded from the game itself, and then we’ve done some post processing, mostly focused on smoothing out the player’s head movement.

Are there any multiplayer modes? Deathmatch?

We’re not planning on supporting any multiplayer modes at this point.

Is this as linear as traditional Half-Life games have been, or are there open sections of the game?

This is a traditional Half-Life experience, so it’s fundamentally a one-way journey. Half-Life has always been about experiencing a hand-crafted, meticulously designed path, where every space is the result of a team of people thinking about what’s in it and why it’s interesting. Some of those spaces afford multiple ways to navigate through them, but you’re always moving forward overall.

Will you need to manually manipulate various parts of guns (and other objects) to use them? Is there a more automated mode for guns?

Half-Life: Alyx’s core combat skill is about using your hands to interact with your weapons efficiently. Reloading is the first of the weapon interactions that you’ll learn. Alyx’s pistol has a multi-step process to reload it, and we see almost all players starting out fairly clunky, doing each step in isolation, but after a bit of practice they start to blend it together. Soon it becomes one single, smooth process, after which we often see them start to put a bit of flair into their movement. But eventually they find themselves having to do it while a zombie is right in front of them, and it all goes to hell. Some players have cited the moment where they fumbled and dropped their magazine at the foot of the attacking zombie as the highlight of their playtest.

So, yes, there’s a fair amount of manual manipulation of weapons, some related to reloading and others related to special functionality. In some cases, the same actions can be performed by buttons on the controller. The rules for this vary between the weapons, because we wanted each weapon to feel like a new and interesting object to interact with, and eventually master. We are aiming to have a wide set of accessibility options for players with limited motor capabilities, so there will be automation options.

What is the recommended playspace for room-scale with Alyx?

We’ve been testing many different sized spaces throughout the project, so as a result, we haven’t built with any specific playspace size in mind. We also fully support standing and seated modes, whether you’re using room-scale or standing room only.

Have you tested full consecutive playthroughs of the campaign with lots of people? How much have you found players able to handle a VR story game considering many people can’t handle long stretches in VR?

Early on in the project, we looked at SteamVR’s data to see how long players were spending in sessions, and tried to fit Half-Life: Alyx’s experience to it, mostly from a pacing perspective. But once we had the first hour or two of the game built, and started playtesting it, we found that literally every player would spend longer in the session than we expected. It was very common for them to end their session, and their first comment would be “Wow, that was the longest I’ve ever been in VR!”. As the game grew longer and longer, and our Index hardware prototypes improved, we saw players increase their session lengths even further. Today, we generally see playtesters go for 2-3 hours before taking a bathroom break. Even subtle improvements seemed to have significant effects, like the way the Index controllers allowed players to open and relax their hands without dropping the controller.

Is it designed to be played in small chunks? Can you save whenever you want and pick it back up? Checkpoints? Something else?

We really like to allow players to experience games in the ways that work best for them, even if the designer in us wishes to have tighter control. So yes, you can save and restore anywhere you like, the same way you could in previous Half-Life games.

Correction, December 12th at 1:34AM ET: The Index controllers are strapped to your hands, not to your wrists.