Baldur’s Gate: Dark Alliance

Easy money
You can perform this trick at any point in the game. Save the game near a shop. Drop all your expensive items, then load your saved character to the same location. After the loading screen, pick up all your items and sell them. Do this again in the exact same order. You will get a lot of money.
(Thanks to kelsey@yahoo.com)

Extreme mode
Finish The Gauntlet level to unlock extreme difficulty.
(Thanks to kelsey@yahoo.com)

Play ss Drizzt
Choose to start a NEW GAME at the title, select any character, then hold L and R until the game starts.
(Thanks to kelsey@yahoo.com)

The Gauntlet level
Finish the game under any difficulty.
(Thanks to kelsey@yahoo.com)