[1][2] The primary task is to build a dungeon, an underground lair which serves as a home to the player's units and their base of operations.

In dungeon building mode, the player controls the world with a hand, performing actions such as moving creatures around the map, casting spells, and interacting with specific items.

[6][5] Additionally, the dungeon heart room stores gold and features a trap door that can be used to get rid of unwanted units.

[6][5] "Evilness" is a resource generated by capturing certain places in the over-world and is needed to research stronger technologies and upgrades.

[5] Almost all units demand a number of comforts, including a regular wage, rooms to sleep in, food and relaxation, and will go on strike if their needs are not met.

[6] The game features both neutral units and rooms, such as a treasury and farms, as well as three factions that provide their own specific advantages and disadvantages: The Horde allows the player to hire goblins, orcs and naga and provides access to training rooms and traps;[8] Demons consist of imps, arachnids and succubi and allows the player to research upgrades as well as generate mana for spells and advanced traps;[8] and The Undead faction offers banshees, vampires and lich creatures and rooms like a prison to incarcerate attacking heroes.

[6] Unlike in the dungeon, players can select units like in other real-time strategy games and issue commands directly as well as use their skills.

[3] After conquering the lands above, the Dungeon Lord becomes bored and attempts to invade a new continent which fails due to the minions' incompetence in boatbuilding.

After she slaughters the people in her home village, she decides to let her dark side take over and begins serving the Dungeon Lord as its chief lieutenant in her quest to punish Tanos for attempting to convert her.

[12] More so than its predecessors, Dungeons 3 contains a lot of allusions to other works of science-fiction and fantasy as well as meta-humor, which includes frequently breaking the fourth wall by both the narrator and Thalya in dialogue.

According to the developer, the introduction of the over-world as an area to be captured in Dungeons 2 has proven a successful addition to the formula which is why Realmforge Studios concentrated on expanding upon this concept while keeping the changes that players liked from the last game.

[15] It is the first entry in the series that was released on multiple platforms, i.e. Microsoft Windows, macOS, Linux, PlayStation 4 and Xbox One, at the same time.

[9][2] German magazine GameStar noted positively that the fact that different resources only exist in the over-world or in the underground forces players to care about both areas.

[9] On the other hand, PC Games criticized the dungeon building aspect for always relying on the same pattern since there are no missions in which a scarcity of resources would force players to change their approach.