Instructions
Walk and crawl slowly on the sides of the walls in the game when approaching your enemy. You don't want the enemy to hear your footsteps or hear you move.
Duck behind trucks or objects such as barrels when trying to shoot the enemy. Peek from behind the truck or object just a little bit to see if the antagonist is facing you. If he isn't, kill him.
Hide in a blizzard in the snowy levels in the game. Wait until there is a very high fog or blizzard and run through it to avoid being seen and use this opportunity to eliminate your enemies.
Lay flat on the snow or on any surface to avoid being seen by trucks or enemies who are walking on hilly surfaces. You may want to move backwards and up against a corner such as up against a wall to avoid being seen. Wait until an enemy approaches and use your target on your rifle to shoot the enemy dead.