Unlock Lucia's Extra Level and Outfit
First Play Lucia's mission 1, then save the game. Reset the PlayStation 2 and wait for the "Press Start button" message to re-appear. Now Press L3, R3, L1, R1, L2, R2, L3, R3. A sound will indicate correct code entry. To get the outfit pick load game and press L1 or R1. Just load a game to get the new level.
Unlock Dante's Extra Level and Outfit
First Play Dante's mission 1, then save the game. Reset the PlayStation 2 and wait for the "Press Start button" message to re-appear. Now Press L3, R3, L1, R1, L2, R2, L3, R3. A sound will indicate correct code entry. To get the outfit pick load game and press L1 or R1. Just load a game to get the new level.
Get Lucia's Diesel Outfit
During gameplay press L1, l1, Triangle, Square, L2, L2
Get Dante's Diesel Outfit
During gameplay press R1, R1, Triangle, Square, R2, R2
Unlocking Must Die Mode
Use either character to finish the game using Hard Difficulty Setting
Get Lucia's Extra Outfits
1st Outfit - Finish the game with Lucia
2nd Outfit - Finish the game with Lucia using Hard Difficulty
3rd Outfit - Finish the game with Lucia using Must Die Difficulty
Get Dante's Extra Outfits
1st Outfit - Finish the game with Dante
2nd Outfit - Finish the game with Dante using Must Die Difficulty
Get Bloody Palace #1 and #2
Finish the game using both characters to get Bloody Palace and finish with both characters on Must Die Difficulty to get Bloody Palace #2
ARIUS' SECRETARY
Okay, in order to get Arius' secretary, beat Lucia's hardest mode, Lucia Must Die mode. If you don't already know how to get this, just beat the game with Lucia on hard mode, to get that beat the game on Lucia's disc on Normal Mode(you already start with this mode when you first play the game).
COSTUMES/BLOODY PALACE
To get different costumes, just beat the game with either Lucia or Dante on Normal, Hard, or Must Die mode. You can also get a mode called Bloody Palace, this is kind of like a secret room, where you fight swarms of enemies and when(or if) you win, you get sometimes a blue orb fragment. But you always get a white orb, a green orb, and a bug red orb, and you also win the bounty of red orbs left by your slaughtered enemies.
TRISH
Now, to get Trish from the first Devil May Cry game, beat the game on Dante's disc on Hard mode. You get Hard mode the same way you get it on Lucia's disc. Trish has all the same controls as Dante did on the first game, but the best part is...Trish can be played on both discs!
Hidden Unlockables
Beat the game one normal mode, not easy automatic, and you will be able to change costumes with the characters you beat each scenario with. For Dante, you get A DIESEL outfit which includes jeans, a brown leather jacket and some accessories. Lucia gets tight jeans and another jacket. The alternate costumes are very cool, and worth playing through the whole game for. Another bonus is that if you beat the game with machine guns, rocket launcher, merciless and vendetta, etc. you can start anew game with all these weapons with their upgrades and all your previous orbs and life as when you beat the game.
Sparda
While in battle when your life gets in the red. Devil Trigger and instead of becoming your normal demon form.Dante will transform into Sparda. This is very effective against bosses and swarms of enemies, so dont use those vital stars, and turn into sparda.
Saving Devil Trigger doing fancy tricks [in devil mode]
Tired of wasting DT (Devil Trigger) while trying to get Show Time combos? Now your problem is solved!!! First turn on your DT and start one of your devilish tricks that drains your DT real fast. (ex. start a sword combo then after Dante or Lucia's 2nd swing pull back on the control stick.) Then after he/she charges and is about to release press your DT button and start hitting triangle to return to normal and they will perform the attack in normal mode and it will do the same amount of damage!!!
Lots of Red Orbs
On the level where you must escape the burning building before time runs out, as soon as you drop down the elevator shaft at the beginning, several homomsiras attack you, beat a few of these with your sword in order to get a "Show Time" rating, once you get that rating pull your pistols out, pistols should be at least level 2 or higher and start shooting, as long as you keep shooting and dont get hit, you will keep your Show Time rating( killing a bad guy with this rating releases more red orbs.)Each homomsira you kill like this releases about 160 red orbs, and an infinite supply of homomsiras appear. The timer on the level is 11 minutes, but don't worry about it, just keep killing those bad guys, because when time runs out the only thing that happens is you have to start the level over. Each time you do this correctly you should get about 20,000 red orbs and you can do it as many times as you like.
Lucia and Dante's Weapons--
Dante Swords
Rebellion- Standard
Merciless-Mission 14
Vendetta-Mission 10 (but I'm not sure)
Dante's Guns
Handguns-Standard
Submachine Gun-Mission 11
Shotgun-Mission 4
Missile Launcher-Mission 9
Lucia's Swords
Cutlaseer-Standard
Klyamoor-Mission 7
Zambak-Mission 10
Lucia's Arsenal
Throwing Daggers-Standard
Darts-Mission 5
Cranky Bomb-Mission 5
Bow Gun-Mission 7