Every time you defeat a Polter Box, you will get a very good item such as materials, seeds, icons and even coins. However, in some locations, you cannot find a Polter Box. Try to get it by hitting the Polter Box icon using the treasure chest left behind by an enemy that you just killed. Note: Only some treasure chest contain the Polter Box icon. Others will have spikes, stones etc.
New Black Enemies
By killing 1,000 of the same variety of monster eg: Kill 1,000 Rabites, you will permanently replace that monster with a new, Black version of it. The Black versions of monsters are a lot stronger and tougher than their regular counter-parts, but have a relatively good chance of dropping Crystal Ores which can be used for forging.
To see a brief sequence involving a chocobo, wait five minutes after the ''Fin'' screen appears when you complete the game. After the scene, the game will go back to the title screen.
Heal dead allies
If your ally is dead, simply save at a Mana statue. Then heal him with an Angel Grail. Go to another room and get killed by monsters, and you'll end up back at the statue, with your ally alive. Check your inventory: it'll say you didn't use an Angel Grail at all
Hit Twice With Bow
This glitch may be hard at first, but after a while it will come naturally. Just equip the Bow and get very close to whatever you want to attack, then attack. If done correctly, it should hit the enemy twice, once when it was being pulled into the Bow, and again when it was released
Get Expert enemies
Kill over 1,000 of the same enemy to replace it with an much more difficult black version of it in future encounters.
To do a special charge attack, wait until your attack gauge is full and your character starts flashing green. Hold A for approximately two seconds, and release it. Your character will do a charge attack which varies with weapon to weapon.
Get Easy experience
In the room before battling Count Lee, there are four bats flying around. If you kill each one, you may get an object. After a few seconds, the bats reappear. Keep killing them and after awhile you will get easy experience.