She's not alone in finding the underwater camera a bit hard to stomach. It's times like this when I almost wish I wasn't immune to simulator sickness (with the exception of low FPS VR); it would certainly help with debugging perceptual problems like that. My guess is that it may be due to the camera being farther away when looking/swimming down (a side effect of the way orbits are setup in the camera plugin I use), causing a sort of roller coaster effect while swimming down. I'd be interested in hearing if swimming purely horizontal—without going up or down—is easier to take. If so, I could possibly fix it by interpolating to a more uniformly spherical orbit while underwater. This would be possible to disable in the settings menu, because I personally quite like the pull back while diving down.
The good news is that the scrapyard doesn't have swimmable water. So, there's time to test ways to mitigate underwater sickness before I get into adding proper underwater content.
That aside, development's been going reasonably well. I started down the GUI rabbit hole, since I definitely want a functional menu system before the scrapyard update. And, I may push that into the demo before the scrapyard itself, given its importance.