Explanations about dynamics of the game

I would really like to have some explanations on the dynamics of the game… especially from level br 10 onwards,
every time I hit an enemy even more than once he never dies, every time they hit me even just on the tracks I die on the first shot, and yet I have crews at the maximum.
It is clear that it is the game that decides who must live and who must die… you can do what you want, sometimes you shoot 2/3 shots on the side of the enemy and he does not die then just one shot from the front and you are dead, it is a highly frustrating situation and not at all fun…keep going like this you are on the right path!!!