Unlock Extreme Mode:
Beat the game on any setting.

Unlock Artemis and Drizzt:
To unlock Artemis the Human and Drizzt the Drow Ranger you must complete the game on Extreme difficulty.

While playing, press and hold Left trigger + Right trigger + Y + A + B + X.Then, with them still held down, press Start.

You can return to normal gameply by pressing B after a level warp.

During gameplay, press and hold Left trigger + Right trigger + Y + A + B + X.