Avoiding the turrets
Roll all the way and, don't run, when the turrets are shooting at you.
All FMV Sequences
Enter "SEECOOLMOVIE" as a password under "Load Game".
Defeating Algo
On the last mission, when you have to fight Algo, to kill him quicker aim for the muzzle when he fires then move up slightly and fire. This will kill him faster.
Defeating Jong Ho
Equip the .45, then hide behind the crates to the right of the full ammo supply. Place your center bead on him and fire. He will eventually die. Do not worry about getting a clear shot, as you will see with incoming enemies they will die easily.