The "Ditman" glitch
This glitch allows you to move 2x faster than normal and is useful when doing speed runs and for doing certain glitches around the game.
To do the glitch)
You must have purchased the striker from the merchant and it doesn't require for you to upgrade the gun.(you can if you want to)
Press R1 to take out the striker but before the laser sight shows up, press Start to bring up your inventory and select another weapon of your choice. Now that you equipped another gun besides the striker, you should notice Leon move much faster than usual and this glitch is useful when you want to make it through a horde of zombies without getting harmed. Please keep in mind that this glitch wears off after entering a door with green letters or going up the stairs.
Unlock Separate Ways Mode
Complete the game to unlock this feature which is a mini-game which revolves around Ada Wong's involvement in Resident Evil 4 and her connection to Albert Wesker, a former member of STARS, who is now attempting to revive Umbrella.
Unlock Professional Difficulty
When you complete the game this difficulty setting will become an available option.
Unlock Special Weapons
When you complete the following tasks the corresponding weapon will become unlocked.
Unlock Infinite Rocket Launcher - Complete the game.
Unlock Chicago Typewriter - Complete Separate Ways mode.
Unlock Handcannon - Earn a five star rank for each Mercenaries mode level.
Unlock P.are.L. 412 - Complete the game under the Professional difficulty.
Unlock Mercenaries Mode Characters
When you complete the following tasks the corresponding character will become unlocked.
Unlock Ada Wong - Earn a four star rank or better on the Pueblo map.
Unlock Albert Wesker - Earn a four star rank or better on the Waterworld map.
Unlock HUNK - Earn a four star rank or better on the Island map.
Unlock Jack Krauser - Earn a four star rank or better on the Castle map.