I just finished playing your current build and it feels far more comfortable than I thought it would be, no form of motion sickness altough I do a fair bit of VR work so maybe not the best candidate but I tried this first thing before my morning coffee 
. As far as feedback I felt the length of where I could zap to seemed too short and the arc was at a very high angle restricting me from moving as far as I liked, maybe make the arc longer with less of an angle so it resembles more of a straight line with a slight bend. It was very fun to zap to the side of walls high up and shoot down on NPCs. I was thinking that maybe adding a subtle grid to the screen effect could help cleanup any motion sickness issues as this would create a static object for the brain to concentrate on similar to how VR cockpits work by having a static object that doesn’t move relative to the player, but this could be very subtle fading out towards the center of the vision much the same way your FOV trick works.
I’m curios would you mind shedding some light on how you achieved the FOV effect, is it a sphere mesh around the player or some type of post process effect??
Really liking your progress