What browser are you using? I tested it on Firefox and Chrome and didn't get any slowdown. But just now I tested it on Edge and it was a laggy mess. The difference was huge. Edit: And now it was fine in Edge apart from long loading. I don't know what's going on there.
The hitbox is the witch (not the hat, not the cape), but yeah, that's never communicated to the player (and you can't tell how thin/wide she is under the cape, she's as wide as her head/hair).
Input is better on joystick since you can control how fast you go. For keyboard we should have introduced a button to hold to go slower/faster so you can rush to the orb but also manouver yourself into a safe spot with precision. But alas...
Thanks for the feedback.