Stay in the hallway till you see Mara. Aproach slowly with the walk button. Equip the sniper rifle, aim in first person view mode. Aim for her gun. Then after that situation is defused climb up the dino's tail.
The Way to kill the flame thrower boss is in first person aiming at the pack on his back.
Once you get past the missle bunker you will find your self on the roof being attacked by a helicopter...Hold R1 to auto aim and then use the roll button (circle) before the light on the helicopter hits you... as it flys overhead blast the hell out of it, and repeat.
On the first level Georgia street go in to the bar,waste the in the room climb through and out the window ,climb on the box climb on the top ledge, run to the end.
Climb on to pole go across kill the idiots that shoot you(with an M-16) carrie on across the pole pick up the M-79 go down and through the window out there head left carrie get the M-79 out and through to kill Kravich it's the easiest way to kill him.