Resident Evil 2

Playing as Ada and Chris Redfield
Finish both scenarios with rank A. You will receive powerful weapon, the 'Hunk' Mission, and another one called 'Ex-Battle' that wasn't available on the PSX version.

In 'Ex-Battle' Mission, you can play as Leon, Claire, Ada, and a bonus character from the first Resident Evil - Chris Redfield. Each character will have their own arsenal. The Mission is to find 4 anti-BOW bombs in the Police station. The characters will start from the lab and must backtrack to the station to find it. There also a time record for the fastest player.

Alternatively, you can play these special Mission, including 'Tofu' by accessing Windows 9x's registry editor. Search for HKEY_LOCAL_MACHINE SOFTWARE CAPCOM RESIDENT EVIL2 and enter the value '8'.

Infinite ammo
To get infinite ammo acess the item select screen then press up,up,down,down,left,right,left,right, aim. After this happens the ammo under your gun should change to an infinite sign.

Leon and Claire's secret outfits
To play Leon or claire in different outfits, you must first select "original game". Then select "normal" level. Play the game without collecting anything. When you get to the place where you can't go back outside the gate and the only place to go in the police station, go down the steps. There you will find a S.T.A.R.S member. He was the helicopter pilot in Resident Evil 1 who saved the S.T.A.R.S members (and almost killed them).By now he is a zombie. Kill him using whatever you have left and search his body for a key. Once you have the key, go into the police station and go to the darkroom(where you develop film.) There will be a locker there. Open it with the key and you will find two outfits for Leon or Claire.

Super Stamina
For limited invulnerability, mix the green, blue and red herbs in that order. You MUST mix the herbs in that order, or they will not work. Green and Blue MUST be mixed together first, then you add the red herb.