Killing all enemies with the Shadow Strike is no problem. Doing so via Bird of Prey is also no problem. Doing both in 63 seconds is a bit of a problem.
Start your run in the direction you're facing, toward the sunset.
Kill the first orc, and the next, then turn back sharply to your right and head into the middle city.
Run through the elfshot here and all the way to the end of the ledge, then aim right for an orc on a corner.
Jump toward the statue-you'll two targets. Aim for the higher one.
Turn back to get the lower one, then turn back again and hop from wall to to wall to reach the catapult. This will give you a vantage on the orc up and slightly to the right.
Turn left for a ridgepole kill.
Just slightly left, at the base of a tower.
Right, in the burned out husk. Your probably saw it on your way in.
Leap right for a kill under the mountains' shadow
Nearly a full 180 for another burnt out husk.
Tun around again- leap up the the wall at tag the nearer, rightmost, orc of the remaining two.
Kill the last orc across the flames.
This is one of the most challenging memories in the game, so give yourself a few tries- you're going to need muscle memory helping you out to get everything in under the time limit.