Of course, enormous spoilers below. I'd assume anyone would only want to read these after their own playthrough.
I just reached "End of Preview" for the first time. By its nature, my first impressions might contain factual errors and will be a bit train of thought. I'll also try to stay critical.
My chief complaint is that the gravity did not feel "always-on". It's easily reproducible -- if I stepped onto a platform tile essentially right as the platform left, my headset would be left hanging in space, without falling and with the freedom to step back. Of course, it's a lot more fun to fear falling than to fall and fail in a game like this, but it seems like maybe some extra gravity check is needed in this particular circumstance. Somehow, the gravity did not feel present in the game as I "wanted" it to -- I know that's not very specific help, but there it is.
A few "dislike moments" in the game quickly became "I appreciate this now" moments. These included learning how to walk backwards on the rolling rock (please don't change the way you can stop walking at the end of the rolling segment and "get deposited forward" onto the platform ahead -- there is a strangely kinetic joy in that happening!), and seeing the second platform maze section (at first it felt like "one too many", but then I realized I was still learning the skill of recognizing the "death pillar" dead ends that would not allow me to escape
"If we could have everything" thoughts (some of these will be silly but hey, train of thought):
* The art assets seemed to get a little repetitive. I wonder if perhaps a next segment could feel like going "deeper into the temple", while maintaining the same gameplay.
* I "paired" (like a fine wine) the "old machinery" controller with the game because the Vive controller felt out of place. Is it worth another art asset to have a similarly themed controller, or perhaps the option for a hand?
* Have you had a chance to look at Knockout Club? When you are hit by a boxer in that game, the screen blurs, I think there might be a red blood-tinge effect, a black-and-white moment, etc... it's really well done. I wonder if there might be the possibility of taking some of those tricks as inspiration for getting thwacked by a "drop block" or the stone sentry or perhaps even just falling.
* I don't really know how you made me feel like I wasn't backpedalling to stay in the same play area "grid" -- I don't even know if it was 3x3 or whatever. Logically I know you had to do it but I didn't feel it. Either you did it artfully or your method truly works splendidly and you are on to something.
* The challenge level of the maze rooms and the nuance of recognizing the pathways and the "death pillar" ends are like legitimately intermediately difficult puzzles. Obviously this stuff is totally subjective, but I personally love death and retry without getting frustrated, but I do know that puzzles can also be divisive. For me, I had absolutely zero temptation to abandon the game and I felt great on completion of each room (of course, I had to wave at the stone sentry while leaving because I felt like it had earned a goodbye), but I wonder if there is some significant part of the audience who might find these places frustration or at least note them as a negative even though I thought they were a strong part of the experience... not sure how else to say this, frustrating but fun for some is frustrating but not fun for others... playing devil's advocate because I like intense experience, but learning the mechanics is obviously a fail-and-replay situation for these rooms.
* There is a different feel between the open areas, the tighter areas, and the "on a ride" corridor dodging areas. I don't know if you are still doing level design, but I wonder if there is some way in your gameplay mechanics to also make a greater use of blind corners and leaning. I love using blind corners, cover mechanics, and leaning in roomscale, and moments where these abilities were relevant in this game seemed a little bit few and far between.
I was in a 2.5m^2 play area and my only negative is that in some cases holding out the torch would reveal the chaperone walls.
Some of the subtle touches, like being able to see the "drop-walls" if perceptive enough, and the levels of indentation letting me sort of bodily plan whether to sidestep or duck, were truly great. Also, the "atmospheric sections" -- like the rides on the lifts to return to the doors locked by "room keys" and watching them unlock -- really worked well. For whatever inexplicable reason I liked being carried for these short segments, they worked well for me if not overdone.
Paragraph of praise:
I tried to stay critical in the above in the spirit of feedback and the hope that at least some of it makes sense. I was probably predisposed to liking this game -- it's kind of a fantasy of the room space environment to use physical walking as the only source of locomotion in a VR environment ("Waltz of the Wizard" does this well too, even though it's a completely different game). This was a wonderful motion platformer experience, and it felt truly unique. Way better than I anticipated.
Etc., etc. I really think you're on to something. Let me know if you would like more technical feedback but I didn't seem to encounter any real bugs on this single playthrough, so I had to get creative. I look forward to trying future builds.