Dungeon System/mk2
The dungeon system of Hyperdimension Neptunia mk2 is a complete redesign from its game predecessor, Hyperdimension Neptunia. Random encounter is removed, and mechanics of Treasure Search is re-done. Skills like Hammer Crush and Monster Call are not present.
Treasure Search

Inside the dungeon, the leader of the party is able to use this ability. The character will emit a purple sonar that reaches through a certain radius per use. When the sonar hits a hidden treasure, it becomes visible and available for pick-up. The ability has no recharge time, allowing the player to use it indefinitely.
There is only one hidden treasure per section of a dungeon, but they will respawn if the player leaves the dungeon.
The icon representing the hidden treasure is hidden in a map unless it's made visible by the ability or by having the Dowsing Rod DLC installed.
Monsters
Instances of monsters are present within a dungeon. By attacking a monster, having it walk through the leader character, or attacking it, a battle will engage.
Symbol Attack

The player can take the initiative by attacking a monster instance before the leader character and monster comes in contact with each other, which will start a battle. With a Symbol Attack, the player's turn comes up first in the battle. If the character's level is too high for the monster, attacking the monster instance will simply make it disappear.
Enemy Advantage
If a monster instance comes in contact with the player from behind, the monster(s) will gain advantage and have its turn(s) first.
Scripted events

Sometimes, a dungeon may contain a Sharicite Symbol. Approaching it will trigger event(s) that is related to the game's story.
Objects and Instances
There are other objects and instances that the player can interact with in a dungeon.
Save Point

The player can save in a save point and continue on from the point when the file is loaded.
Gathering Point

The player can gather Materials from Gathering Points, symbolized by a green question mark.
Common Item

Common Items contain items that the player can use. It can range from any type of items except for Materials. Common Items don't respawn once they're gathered.
Dungeon Exit

The only way to exit a dungeon is through a Dungeon Exit.