Full list of all 75 Borderlands 2 achievements worth 1,875 gamerscore. It takes around 60-80 hours to unlock all of the achievements in the base game.
The base game contains 69 achievements worth 1,625 Gamerscore, and there is 1 DLC pack containing 6 achievements worth 250 Gamerscore.
Defeated Terramorphous the Invincible
Reached level 50
Killed a flying enemy with a thrown Tediore weapon
Killed 100 enemies with the Sabre turret
Got an item from Michael Mamaril
Gave Claptrap a high five
Fed thy noble queen 3 times during one visit to her quarters
Completed thy quest by rescuing yonder queen
Completed the mission "Long Way To The Top"
Wielded the Mysterious Amulet
Showed thine worst enemy, the abomination known as "The Darkness," who is the nerdiest of them all
Unsheathed 5 swords from Immortal Skeletaurs without leaving the area
Introduced thyself to the White Knight
Had Purple-rated gear or better equipped in every slot
Allowed a Goliath to level up four times before killing him
Defeated Jack
Completed the mission "Data Mining"
Completed the mission "Toil And Trouble"
Completed the mission "Where Angels Fear To Tread"
Reached level 25
Completed the mission "Shoot This Guy in the Face"
Slew Mister Boney Pants Guy
Phaselocked 100 enemies
Killed a Chubby
Tipped Moxxi $10,000
Completed the mission "The Man Who Would Be Jack"
Completed the mission "The Once and Future Slab"
Completed the mission "X Marks the Spot"
Completed the mission "Bright Lights, Flying City"
Completed the mission "Rising Action"
Completed the mission "A Train To Catch"
Completed 20 side missions
Completed the mission "Wildlife Preservation"
Killed a Constructor without it ever building another bot
Completed the mission "A Dam Fine Rescue"
Purchased 5 items from the black market
Completed the mission "Hunting The Firehawk"
Redeemed 25 tokens
Completed the mission "Plan B"
Reached level 10
Completed the mission "The Road To Sanctuary"
Completed the mission "Best Minion Ever"
Unlocked 10 customization items
Revived someone from "Fight for Your Life!" that is on your friends list
Reached level 5
Completed the mission "My First Gun"
Complete level 1 of all non-level-specific challenges with a single character
Complete Round 5 of any Circle of Slaughter
Discover all named locations in Three Horns, Tundra Express, and Frostburn Canyon
Discover all named locations in Sanctuary, Opportunity, and Lynchwood
Discover all named locations in The Highlands, Thousand Cuts, and Wildlife Exploitation Preserve
Discover all named locations in Eridium Blight, Arid Nexus, and Sawtooth Cauldron
Discover all named locations
Gunzerk continuously for 90 seconds
Kill Donkey Mong
Hidden
Remain in Zero's Deception mode for ten seconds straight
Complete all side missions
Discover all named locations in Oasis and the surrounding Pirate's Booty zones
Complete all Pirate's Booty side missions
Complete all Campaign of Carnage side missions
Collect 10 pictures of Moxxi in Campaign of Carnage
Complete the mission "The Fall of Nakayama"
Complete all Hammerlock's Hunt side missions
Discover all named locations in Hammerlock's Hunt
Win the most challenging round in Murderlin's Temple
Demonstrate your skill, or lack thereof, at rolling the magical treasure orb of many sides
Vanquish the Ancient Dragons of Destruction
Defeated the Dark Web.
Defeated Haderax the Invincible.
Allowed Tiny Tina to arm the moonshot cannon.
Completed the mission "Paradise Found".
Activated the Backburner's firewall.
Equip effervescent-quality gear in all slots (except class mod).