I applaud your exemplary skill. I still want to make it easier, because I suck at these games, but still enjoy them.
The 30mm GAU-32C will grind your enemies into dust, just point the barrel towards the enemy and hold down the trigger.
Smoke grenades work like a wall and turn off the brains of enemies on any mission except the 2nd. On the 2nd mission, just take incendiary grenades and a scatter gun.
Go, do a crime.