What is the difference among the difficulty levels?
There are 4 levels of difficulties for each Quest: [NORMAL], [HARD], [Z-HARD] and [SUPER].
Also, there are some routes on the map not accessible on certain difficulties.
Each event stage has 6 levels of difficulty: [NORMAL], [HARD], [Z-HARD], [SUPER], [SUPER2] and [SUPER3].
Rewards will be better the higher the difficulty, and encounters with opponents will become more difficult as well.