Unlock Almost Everything
At the start menu hold L1 L2 R1 R2 then rotate the Left Analog-stick. You will here a voice say "Devil May Cry and all modes, costumes, and galleries will be unlocked. Note that you must still complete the stages and buy your skills normally. This code is verified for the U.S. and Japanese versions only.
To unlock Hard Mode beat Normal Mode
To unlock Dante Must Die beat Hard Mode
To unlock Heaven or Hell beat Dante Must die
Unlockable: Alternate Ending
Kill 100 enemies during the credits to get a different ending screen.
Press R1 or L1 at the mission select screen to get different characters.
Beat the game on easy for shirtless Dante
Beat the game on normal for Devil May Cry 1 Dante
Beat the game on hard for shirtless Devil May Cray 1 Dante
Beat the game on hard to unlock the Legendary Dark Knight
Beat the game on hard to unlock Sparda
Unlockable: Infinite Devil Trigger
Beat Dante must die mode to unlock the Devil Trigger.
Get Devil Arms
Cerberus - Complete Mission 3.
Agni & Rudra - Finish Mission 5.
Nevan - Complete Mission 9.
Beowulf - Above the starting spot in Mission 14.
Yamato - Play as Vergil in Mission 19.
Force Edge - Unlock and play as Dante from the first DMC third character if all are unlocked, shirtless Dante, and/or Legendary Dark Knight.
Shotgun - Inside the bar in mission 3. This is after unlocking the blue exit door.
Artemis - Find and use all three essences on the laser machine in mission 5.
Spiral - The outdoor area in mission 9 has a high area near a waterfall; jump to the high area for the gun.
Kalina Ann - Defeat the mission 16 boss.
Tap L2 after firing a slow to reload weapon i.e., shotgun and flick it back to fire it again. It is slightly faster than waiting for the weapon to reload.