Here is the full list of all 30 Tiny Tina's Assault on Dragon Keep: A Wonderlands One-shot Adventure achievements worth 1,000 gamerscore.
Purchased 5 items from the Black Market.
Completed thy quest by rescuing yonder queen.
Used the Lootapult to cause a Lootsplosion
Redeemed 25 tokens.
Unlocked 10 customization items.
Unsheathed 5 swords from Immortal Skeletaurs without leaving the area.
Introduced thyself to the White Knight.
Reached level 10.
Revived someone from "Fight for Your Life!" that is on your friends list.
Reached level 5.
Slew Mister Boney Pants Guy.
Complete the first rank of all non-level-specific challenges with a single character.
Reach level 25.
Reach level 35.
Have Purple-rarity gear or better equipped in every slot.
Kill 100 enemies with the Sabre turret.
Phaselock 100 enemies.
Gunzerk continuously for 90 seconds.
Kill a Chubby.
Remain in Zer0's Decepti0n mode for ten seconds straight.
Hidden
Complete all side missions.
Feed thy noble queen thrice during a single visit to her quarters.
Show thine worst enemy, the abomination known as "The Darkness", who is the nerdiest of them all.
Win the most challenging round in Murderlin's Temple.
Wield the Mysterious Amulet.
Demonstrate your skill, or lack thereof, at rolling the magical treasure orb of many sides.
Vanquish the Ancient Dragons of Destruction.
Use Deathtrap to kill 100 enemies
Get 100 kills while in a Buzzaxe Rampage