HL:A definitely does more with something resembling an adventure formula akin to the traditional HL games, versus most other VR titles. Per my original comment; I think I have to consider it as experimenting, and it's only partially successful.
(low-level spoilers)
There's one moment early on where you're asked to solve a vorgon puzzle in a drainage ditch. Every person I've asked who has been through this area disliked it, and I haven't found anyone who solved it legitimately. Its confusing. It has parallax/perspective elements which ask you to move around a large area, position yourself perfectly, and possibly even crane your neck in the right way to get an angle on what is the intended solution.
But, movement sucks in any non-room-style VR game. You can't use the joystick to just move your character, like you would in a non-VR game, because it causes unreal motion sickness in, like, 100% of users (this is available as option. its an experience that i think everyone should try; I had no idea I could get motion sickness until I did, but I was literally falling over). Instead, you press the joystick in the direction you want, a targeting beam pops up, and you "teleport" to the desired location. This sucks. Its imprecise, its slow, and it makes you feel, to some degree, like you're actually watching a powerpoint presentation of the game.
And, head yaw can also suck in VR. This may be surprising; its the entire point of VR. But, depending on whether your headset has a tether, and how big your play area is, many VR players are stuck stationary and with, maybe, 180 degrees of freedom in front of them. In one of these setups, you cant naturally look behind you; you have to rotate in-game, which calls back to all of the negatives that movement itself has. But even the in-game rotation is in-precise; in HL:A, it jumps by roughly 60 degree increments. Imagine there's something 45 degrees to your left you want to center; you can either turn your head 45 degrees left to center it (uncomfortable), rotate your body 45 degrees left (scary), or rotate in-game 60 degrees left, followed by rotating your head 15 degrees right or body 15 degrees right. In small play areas, the body rotations are a slippery slope that eventually ends in you being turned around, contacting furniture, or getting tangled in the headset tether. This is, at least for me, always front of mind; I can't escape the reality that my play area isn't large. So, you end up with these nearly (only nearly) subconscious calculations involving how many times you need to rotate in-game to make neck rotations less uncomfortable.
This is the problem space that any non-room VR game has, and will have, to solve. It is unsolved. I believe it is unsolvable. Even if you can get the player/object interactions down to perfection (this is insanely difficult, and different for every game; HL:A is the first "complex" VR game I've seen get close), even if you can craft a story and world that is both compelling, and works well with the intrinsic movement limitations VR has (no one has done this yet; again, HL:A gets close), even if you can remove slideshow-teleportation movement without motion sickness (I believe this is impossible without something like an omni-directional treadmill); you still run up against most players just not having the space for room-scale VR & N-degree freedom of movement.
VR is filled with technical challenges, and every technical challenge developers have to solve limits their ability to be artists. This is why arcade-style games are the showcase piece for VR. And, in my opinion, will remain that way for a good, long while.