use the submachine gun
it takes more life out from him ^_^

and also DO TAKE COVER.
Wait for him to shoot the cover. Then when he's on the move, just empty all your ammo into
his flesh!!

also... you might notice that he follows a pattern in the very beginning, so it can't be
too hard (Shooting 3 times, then hiding, then running away to another cover!)

and when he's behind the arcade console you could blow that up too. also the speakers
behind which he shelters are inflammable! :)