At the train station when the two guys in black are walking behined Ethan, shoot Ethan until he falls down and then quickly shoot the guy in the front. Ethan will jump up and kick the other guy in the back. He will be invincible to gun fire but dies if some one punches him.
Enter these codes at the stage select screen. If these are done correctly you'll hear Ethan say "there, that's better."
Invincibility: R, Z, C-down, R, C-down (Given by: Stingone)
Unlimited Ammo: C-up, Z, C-left, Z, L (Given by: Stingone)
7.65 Silenced Pistol: C-Up, L, C-Right, C-Left, C-Up.
Uzi with 30 Rounds: C-Right, C-Left, C-Right, C-Down, R.
High Powered 9mm Pistol: R, L, C-Down, C-Up, C-up.
Mini Rocket Launcher: R, L, C-Left, C-Right, C-Down.
Big Feet: C-Down, R, Z, C-Right, C-Left.
Kid Mode: C-Down, C-Up, R, L, Z .
Turbo Mode: C-Up, Z, C-Up, Z, C-Up.
Big Head Mode: C-Down, R, C-Up, L, C-Left.
Giant Head Mode: C-Down, L, C-Up, C-Right, L.