How to unlock Cheat mode:
During gameplay press and hold L + R + Y + A + Left Analog Stick Right then press Start

Play as Drizzt:
Successfully complete the baulders gate section of the game and he will become available. Note: Drizzt is a elf type guy with two scimitars that are the only ones he can use.

Also reported as beating the game on extreme difficulty to get Drizzt