Complete the game on any difficulty to unlock Mercenaries Mode, Infinite Ammo option, New Game+ mode, History of Resident Evil, Sheva Alomar, Chris's Safari alternate costume, and Sheva's Clubbin alternate costume.
Perform the corresponding tasks to unlock the following bonuses:
HOW TO UNLOCK
Classic Horror Filter
Complete the game on amateur difficulty.
Professional Difficulty and "Noise Filter"
Complete the game on veteran difficulty.
Complete the game on normal difficulty.
Unlock Rocket Launcher w/ Infinite Ammo
Complete the game in under 5 hours on any difficulty. Then, enable it at the "Bonus Features" menu.