That One Level

4 vs. Satan
* The first and third Dungeons, as there are enemies that are both powerful and have distracting skills at the same time.
Dragondawn
* The tower from the first map and the cave from the last map because of how the enemies are far more powerful than the previous ones. Worst of all, the latter is also a Marathon Level.
Hero Story
* The two fire levels as you don't have the opportunity to equip the heroes to get to the second level.
The Legend of Devils / Heroes:
* The snake forests are the first sign the game isn't a walk in the park.
* The first dungeon being filled with enemies who are powerful and could temporarily immobilize the hero's party.
* Any dungeon starting with the fifth, as the main enemies have devastating skills.
* Same goes for the last three dungeons leading to the ninth castle.
* The water dungeon and the high mountain dungeon because of how long they are, rather than the enemies being too difficult to beat.