) is an illustration of what I'm trying to describe in Reply #5 (just above) THAT I just happened to watch today/the next day! It's so weird it seems like cookies are tracking everything I do, but no, just cosmic weirdness.
EDITED: For the record I still can't tell how much of my uneasiness is this versus probable distortion. I've tried doing experiments outdoors and the video game still feels off. What I'm playing with is the same thing more or less, except looking up and down, which feels far less intuitive...
Okay, here is a disappointing answer. I find that if I use a view angle that is say 10 or so, this final distortion goes away, and it looks realistic. The only problem is this is unplayable, and almost feels like an orthographic projection. It's disappointing. It feels like the projection matrix method is either flawed, pick your poison, or maybe using a flat screen is flawed and only an infinitely small angle is correct. I know photographs can appear distorted depending on the lenses but they don't seem to be so treacherous as this. I'm so disappointed with these results, I wonder if there are alternatives...
There is a table here that shows this relationship. Funnily it goes to 10 degrees where distortion is fairly minimal as I described. I wonder why looking up and down along poles brings out the distortion so acutely for me. I will be very happy if VR remedies this. Oh well, ignorance was bliss (on the bright side, VR is just around the corner. I really hope it does the trick.)"It is important to notice that a change of 10% in an object´s dimension is clearly perceivable at first sight, as it is the overall distortion with a 60° visual angle or the maximum punctual distortion with a 50° visual angle. To avoid this excessive distortion, the visual angle of the observer should be always under 40°, and the closer it is to 30°, the better."