Sometimes those membranes are tough!The membrane was much tighter before i applied Vaseline - or the duckling has shrunk.
More and more chips have fallen off and the little one is now only being held by the membrane, but still absorbing the yolk. Almost no blood is visible in the membrane, i think that's a good sign?
This is it at about two hours ago - it takes too long to upload those videos...
Once you can see there are no visable blood vessles you can widen that hole around the head area. Sometimes i even use a little pair of snub nose scissors so i don't end up having the membrane rip farther than i intend to. Usually once you've made it to where the head can easily pop out it can push itself the rest of the way out. Get yourself a little Tupperware bowl or cup ready with a clean paper towel in it in case it does come out with an open navel or a bit of unabsorbed yolk.