I seem to occasionally get the "killed X creatures with one blow" bonus, even though I decidedly did not kill X creatures with a single shot. It sometimes happened to me when using "channeled" skills (such as rapid fire) and sometimes even using multiple regular attacks.
What is the exact condition for receiving the bonus? And if it's really "X creatures killed under Y seconds", then what is Y?
Best Answer
From my experience so far, you get Mighty Blow if you kill 6 or more enemies under X seconds.
I have not scientifically measured it, but I think the X is between 0.5 and 1.
It seems completely independent as to the source of the kill - a single skill activation, a channelled skill activation, multiple hits, traps - as long as it's >6 kills in <X seconds, you get the Mighty Blow bonus.