One thing that hit me with every sentence you wrote there was the way you used most of the verbs.
I wanted to change every sentence I read because it seemed so odd to me to read it as:
'Suddenly, out of the corner his left eye he sees a dark shadow leaping at him. Instinctively he ducks and rolls over his right shoulder. '
I read this, then re-read it as
'Suddenly, out of the corner his left eye he SAW a dark shadow leaping at him. Instinctively he duckED and rollED over his right shoulder'
Only my opinion of course, but I felt compelled to change the tense used as I read it, as it feels more natural to me. Maybe just me though...
