My most sensorily confused moment came in (ironically) A Chair in a Room: Greenwater, when I tried to sit on a virtual chair. Very uncomfortable. Incidentally, I recommend Greenwater too, if you don't have it already; not perfect and a bit long in the tooth, but well-told, intriguing and scary as hell.
I went back to the start of Is or Will Be and retreated to the Barnacle room over and over again to kill all the headcrabs, saving my bullets just for the headcrab zombies. Just as well when I came across the Combine soldiers later in the level.
"We all have flaws, and mine is being wicked."
James Thurber, The Thirteen Clocks 1951
Haha, that sounds dangerous. Did you fall flat on your arse? :D VR can have some bizarre effects. I've nearly fallen over bending down and trying to stabilise myself on a nearby wall. There's a bar in Alyx and I really wanted to take a seat and pour myself a drink.
I do have A Chair in a Room but I haven't got very far. I found it a little frustrating, partly the Index controllers trying to emulate the Vive controllers. When Alyx is done I will try it again.
Have you got to chapter 7 yet? :O Oh my god that is some tense crazy shit going on! I had to take a break at one point and lots of swearing!
I haven't found the game particularly difficult. The enemies are pretty predictable (combine are mostly shoot, pause, shoot), head crabs are less jumpy and slower that they used to be, and J*** **********.