[5] The game takes place in a fantasy setting where players control the young apprentices of wizards and warriors and defend against hordes of monsters.

Dungeon Defenders is a mix of tower defense, role-playing, and action-adventure where one to four (sometimes up to six) players work together to protect one or more Eternia Crystals from being destroyed by waves of enemies which include goblins, archers, orcs, kobolds, ogres and other creatures.

The characters can be damaged by enemy attacks, and can be killed in battle but will respawn after a few seconds, unless hardcore mode is selected.

The player can manage up to a finite number of characters, with 40 being the Steam version's limit, though they are kept separate between Trendy's ranked servers and for unranked play.

New equipment can be purchased using banked mana either in the game's store or in other players' auctions or collected from killing monsters, opening chests, or beating the level.

Dungeon Defenders was released on Xbox Live Arcade, PlayStation Network and PC in October and December 2011.

[27] By February 2012, the game's publisher reported over one million sales across Xbox Live, PlayStation Network, and Steam.

It was free on Google Play, but paid on the App Store and featured a revamped menu system and improved controls.

It includes an early version of Playverse, the server system designed for Dungeon Defenders 2 to improve cross-platform support and discourage hacking.

A sequel titled Dungeon Defenders II was made available in beta period for Windows and PlayStation 4 at the 2013 PAX East convention,[31] featuring similar gameplay to its predecessor.

[33] Another sequel, Dungeon Defenders: Awakened was unveiled by Chromatic Games in 2019, formerly Trendy Entertainment before corporate restructuring.

[34] Players that pre-ordered Awakened for any platform gained access to the beta version of the title, which launched in November 2019, on Microsoft Windows.

[39] An action role-playing roguelite spin-off titled Dungeon Defenders: Going Rogue was developed and published by Chromatic Games and released in early access for Microsoft Windows on March 29, 2022.