While banging one's head on the ice comes with the extra motion of the brain bouncing back and forth against the skull, I'm still not so sure we should underestimate the impact of a puck to the head. With today's flexible sticks, even amateur players can get off pretty hard shots. I once blocked a shot that cracked my shin pad.
I don't like to think what it might have done to my head/face.
Anyway you look at it, hockey is a great, but dangerous, sport.
Ouch!