If he is a killbot, why can't i kill the people by smacking objects in their heads?
Also, this game has it's own youtube and soundcloud, so type in U.S. Killbotics, and you will receive an answer.
Tough level hints:
level 3: next to the 3 men there is a gas container shoot the top and shoot the leader.
level 4: shoot the gas tank on the roof, kill all guards, and then shoot petrol tank on helicopter.
Because he doesn't want to kill!