The level of the initial area is set when Unassuming Docks is first visited, but in Normal Mode is at least 30 and at most 35. It is expected that the player has finished the main Borderlands 2 storyline before visiting, though that is not required.
Taking place after the event of Roland's death, Tina and the first group of Vault Hunters decide to play a game of Bunkers and Badasses, Pandora's equivalent to the table top game "Dungeons & Dragons". Tina serves as the "Bunker Master" and narrator of the DLC, and changes the world in dynamic ways as the story progresses, such as altering the appearance of locations and adding characters and bosses.
The plot involves the new Vault Hunters playing characters within the campaign, each responding to Tina's narration in their own way. Their quest is to rescue the queen from an evil sorcerer and restore peace and tranquility to the land. The journey to Dragon Keep ultimately has Tina coming to terms with Roland's death.
The DLC features a whole host of new enemies, locations and a number of new items, including new guns, shields, fantasy-themed class mods, and spell-like grenade mods. Familiar faces from the base game also make a return, including Mr. Torgue and Ellie.
There is also a new system that classifies weapons by manufacturer, precious gem prefix, and color scheme. For example, certain Hyperion weapons appear white with a "Diamond" prefix, while Dahl items can appear green on color with a "Emerald" prefix.
A new type of chest, called a Dice Chest, will appear with two twenty-sided dice (D20s) on top. Opening the chest normally rolls one D20, and the amount shown on the roll will determine the rarity of the loot inside the chest (20 being the highest, 1 being the lowest). Spending 5 Eridium rolls both D20s, and the higher amount will be taken to determine loot rarity.
Vending machines have also been redesigned, with a more fantasy-oriented aesthetic. Reskins of existing characters featuring renaissance-themed garb (Ellie and Moxxi, in particular), and new dialogue for the Vault Hunters is also included.
Assault on Dragon Keep contains many new enemy types including:
- Dragon Keep
- Flamerock Refuge
- The Forest
- Hatred's Shadow
- Immortal Woods
- Lair of Infinite Agony
- Mines of Avarice
- Murderlin's Temple
- Unassuming Docks
- The Winged Storm
There is also a new, rare type of purple rarity weapon available, informally known as Gemstone weapons due to each brand using a specific color scheme and prefix matching a known gem or stone; Hyperion weapons feature the Diamond prefix and are white, Tediore has the Cubic Zerconia prefix with a white and black color, Bandit has the Quartz prefix and pink colors, Dahl has the Emerald prefix and dark green, Vladof is Garnet and dark red, Jakobs is Citrine and has orange metal, Torgue is Rock and dark grey, and Maliwan is Aquamarine with various shades of grey, orange and blue.
- This DLC was originally teased at Pax East 2013, but wasn't confirmed until it was accidentally leaked by Anthony Burch who took a picture of a passed out friend with the poster showing in the background. It has since been confirmed officially and given a release date.
- This DLC has a large number of references, such as items, locations and challenges, relating to content of other famous fantasy games, films, and television shows.
- The original idea for the DLC was to have the Vault Hunters venturing through a Hyperion facility, where the facility's director could manipulate everything and turned it into a big game of Dungeons & Dragons. The concept was changed as the creators felt that having Tiny Tina run the game would give them more freedom to be creative and spontaneous.
- Most elements in Tiny Tina's Assault on Dragon Keep have counterparts in the main story line, e.g. the Handsome Sorcerer is based on Handsome Jack, the counterparts of knights serving the Handsome Sorcerer are the Loaders in the main story line, and so on. Even the plot of this DLC is a fantasy version of the main story line, with similar twists and turns.