Man, this was wild. I was playing with keyboard, sadly, but I still enjoyed the heck out of it. My main struggle was with range; getting the right distance on a curve is harder than it looks.
It was also kind of counterintuitive that the gun swayed vertically by default, but I suspect I would've been even more disoriented if I had to do a vertical curve by leaning sideways and then doing a sideways swing. It's probably easier with controller, where you can precisely control the lean.
Overall, a really interesting experiment in input. I really appreciate experiments like this, even if I can't quite wrap my head around the necessary inputs.