Basically, you are going to need to charge up the hill by using the sides and occasionally running across the road. Start out by heaving a grenade across the street to take out the Nazi in the building who is probably hiding behind the crate. Then run across the street and head to the right, where you can cut a fence. Do so, kill everyone, head up the hill and, when you can't go any further up, run across the street. Now you should be able to head to the left (uphill) and do the same thing that you just did. This should bring you level with the machine gun. Run out and kill everyone around the machine gun, then jump on it (press X) and take out everyone coming up the hill. Unlike most FPS games, the machine gun in HoV never overheats, so go nuts and spam bullets at anything that twitches. When everyone is dead, turn around and head for the star to end the level.