Compared to the original version the IZJS is much better in many ways. The introduction of Job Classes has made the gameplay completely different. Basically, you have to assign classes to all your characters so they can benefits of all magicks, technicks, weapons, etc… that class has to offer. You can of course not assign any class to all your characters and play the game as such. Job classes are not the only add-on and there are many other new/ updated items;
- Treasure chests: To re-spawn a treasure chest you only need to zone out one screen. The treasure chests contains better items. Some Magicks and Technicks are within treasure chests.
- Speed Boost: You can now travel/fight faster by using the L1 button.
- Weapons: New weapons have been added. The strongest one is now the Seitengrat bow but the probability of obtaining it is ridiculously low.
- Enemies: Some enemy stats have been updated such as the Archaeoaevis. Some foes will also drop different loots.
- Espers/ Guests: You can change your espers' and guests' gambits.
- Trial Mode: A new mode where you can battle up to 100 Stages against enemies from the main game including; normal enemies, bosses, Espers and hunt marks.
- Strong/ Weak Mode: Strong mode can only be chosen when you have completed the main game. In this mode your characters will already be at higher levels and you will no longer earn EXP. Weak mode can only be chosen when you have completed the Trial mode. Your characters will start at lower levels from start to finish.
- 9,999 Damage uncap: Your characters can now deal more than 9,999 damage.
The list above is not a complete one. There are more changes than this in-game. For instance, the merchants now sell different items after certain events. Even the Baknamy Merchant has changed location to the Necrohol of Nabudis. To notice all the differences you will have to play this version at least once.