Here are some screenshots of the demo from my ultrawide. It's 3440x1440 @144hz and ran at solid 60fps, but I am using an RTX 4090 so I'd be worried if it didn't.
It seems to respect the aspect ratio so that's good but ideally there should be full support for ultra-wide and it's on my to-do list. Hopefully it will be as simple as changing the window frame-size and maybe some code related to the scrolling and zooming. Thank you for the screens!