Complete single playthrough. This is an interesting experiment of a game, and really quite unexpected to see coming from Introversion given their existing catalogue. The game sees you exploring an underground environment in first-person, the catch being that your only means of vision in the dark comes from a scanning device which outlines surrounding surfaces with dot patterns when directed towards them. Beyond this, there's not much by way of interactivity (a short puzzle towards the end of the game aside), but there's some decent worldbuilding from short (self-spoken) narrative explanation about the area - with some fairly unsettling themes - and the game's fairly short so doesn't overly outstay its welcome.

I wouldn't choose to play it through a second time, but it's worth playing through once for the experience. I'd also say that while I didn't play in VR, I can see that doing so could raise this to much more compelling levels.