Infinite bullets
In the NYPD, go down stairs and enter the room to the left you can find bullets in the box near the counter get it and go to the New York map Now return to that room for more ammo when you need it.

Super tool kit
Give Wayne 14 rare cards and he will give you a super tool kit that you'll find in your inventory.This will able you to upgrade you items with out loosing your items you are upgrading.

Super weapons
Ever wonder what to do with all that junk? Well, take it to wayne and when you give him exactly 300 pieces of junk, he will give you a super weapon.

60 rounds of bullets
On the first level, after you beat Eve on the Opera Stage, go backstage and you will see the hole. If you listen carefully at the hole you will hear sirens. Go back outside the Operahouse and ask the cop on the far right for bullets. He will give you 60 rounds.

Refill PE Faster
To refill the PE bar in battle faster just change armor in battle and then change back, it will return to normal speed.

Chocobo Cameo
After you've visited the museum the first time, go back to it on the map screen. As the helicopter view scrolls around the building, look at the banner.

Infinite Medicine
In Day 3 Selection after the battle in the 17th district where Torres dies, whenever you leave the precinct and come back, visit the weapons room and check the chest on the top right. There will be 2 or 3 medicine there.

Lots of Trading Cards
When you're at the hospital, just before you go to the 13TH floor, find the room that has the nurse who is looking for more hurt people. Now go to the top of the room to the fallen cabinet, look behind it to find lots of tradng cards. Make sure you have room for them in your inventory.