Hard mode
Complete the game once to unlock Hard mode.
Legendary Dark Night mode
Complete Hard mode to unlock Legendary Dark Night mode.
Dante Must Die mode
Complete Legendary Dark Night mode to unlock Dante Must Die mode.
Easy automatic mode
Complete missions 1, 2, or 3 while using at least one continue. When you then start the next mission, there will be an option to change the game to easy automatic mode. Just remember that when easy mode is activated you cannot return to normal mode.
Easy Automatic mode automates most fo the combat functions, allowing easier access to soe of Dante's more spectacular moves.
Super Dante mode
Complete Dante Must Die mode to unlock Super Dante mode. In this Hard mode
Complete the game once to unlock Hard mode.
Legendary Dark Night mode
Complete Hard mode to unlock Legendary Dark Night mode.
Dante Must Die mode
Complete Legendary Dark Night mode to unlock Dante Must Die mode.
Easy automatic mode
Complete missions 1, 2, or 3 while using at least one continue. When you then start the next mission, there will be an option to change the game to easy automatic mode. Just remember that when easy mode is activated you cannot return to normal mode.
Easy Automatic mode automates most of the combat functions, allowing easier access to some of Dante's more spectacular moves.
Super Dante mode
Complete Dante Must Die mode to unlock Super Dante mode. In this mode you can transform into a devil, and use DT indefinitely.
All-star group photo
Complete the game with an "S" rank on all missions and you will unlock the all-star group photo.
Collecting red orbs
When you have killed all the enemies in a room go through a door and then go back in, now your opponents will be back so you can kill them again to collect more red orbs. If you kill them using only your sword instead of a firearm, you will be rewarded with more orbs.
In hard mode when you face the phantom spider for the second time during mission 4, in corridor where he chases you, kill him instead of escaping through the door on your left. Make sure you have your devil trigger fully charged. You will get 500 Orbs after killing him. Save the game, restart the level, and repeat.
Triple or Octuple Stab
Press O twice then wait for 1-2 seconds and then rapidly tap it. Dante should then perform a combo ranging from 2 to 7 stabs followed by a point-blank Stinger.
Skip FMV sequences
Press Select during an FMV sequence.
Swap out Devil Arms
You can Swap out Alastor and Ifrit on the fly by pressing down on the right control stick.
"Bring it on!"
Hold down the R2 button to perform a small taunt that will raise your Devil trigger gauge by one.
(Author's note: That's not all! Remember the cool feature about the PS2 buttons? They are pressure sensitive! Smash R2 down to perform a longer taunt and raise your gauge by 3 or more!)