While playing, hold R2 + L1 + Left + Triangle then press Start. A cheat menu with Level Warp & Invincibility options will be unlocked.
While playing, hold R2 + L1 + Left + Triangle then press R3. Your character will now be at level 20 and have access to all feats. Your character will also have level 1 feats on all class-dependent feats and 75,000 more gold pieces. Your character will not advance to a higher level or gain additional feats.
The Gauntlet level:
Complete the game on any difficulty.
Complete The Gauntlet level to unlock the extreme difficulty setting.
Play as Drizzt:
At the main menu hold L1 + R1 then press X + Triangle. Or, complete the game on the extreme difficulty setting.