-Soldiers are a very tough enemy to fight at first. An easy way to defeat them is to get very close with the shotgun, usually touching them. However, if done on a long strip of land with no cover, you will not survive long. Try hitting them in the head with the pistol, or spray just above their head with the rifle while zoomed.
-When you get in the car after navigating the maze after the monster, you must engage two supers and a couple regular soldiers before you get out. Instead of getting out and losing a ton of health, close the window and start throwing grenades without standing up. This is an easy way to kill all the soldiers, or set them on fire.