Love it!
One minor thing I noticed, is that capturing the mouse doesn't seem to be working on FF 66.0.3 on Linux (Manjaro). Not sure if that's because I have a dual screen setup. I guess on a single-screen setup I wouldn't notice if I had the browser in full screen.
Edit: There is a "lock mouse" button and I am an idiot. Thank you for reading, I will leave this here for posterity.