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.
Remained in Zero's Deception mode for ten seconds straight
Discovered all named locations
Completed all Campaign of Carnage side missions
Completed all Pirate's Booty side missions
Discovered all named locations in Eridium Blight, Arid Nexus, and Sawtooth Cauldron
Completed all Hammerlock's Hunt side missions
Won the most challenging round in Murderlin's Temple
Wielded the Mysterious Amulet
Vanquished the Ancient Dragons of Destruction
Reached level 50
Killed a flying enemy with a thrown Tediore weapon
Discovered all named locations in The Highlands, Thousand Cuts, and Wildlife Exploitation Preserve
I can't even capture it on my camera
Discovered all named locations in Three Horns, Tundra Express, and Frostburn Canyon
Completed the mission "Long Way To The Top"
Discovered all named locations in Oasis and the surrounding Pirate's Booty zones
Completed the mission "X Marks the Spot"
Had Purple-rated gear or better equipped in every slot
Discovered all named locations in Hammerlock's Hunt
Completed the mission "The Fall of Nakayama"
Fed thy noble queen 3 times during one visit to her quarters
Completed thy quest by rescuing yonder queen
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
Demonstrated your skill, or lack thereof, at rolling the magical treasure orb of many sides
Slew Mister Boney Pants Guy
Killed Donkey Mong
Defeated Jack
Completed the mission "Data Mining"
Opened the chest at the bus stop in Fyrestone
Completed the mission "Toil And Trouble"
Completed the mission "Where Angels Fear To Tread"
Completed the mission "The Man Who Would Be Jack"
Discovered all named locations in Sanctuary, Opportunity, and Lynchwood
Completed the mission "The Once and Future Slab"
Allowed a Goliath to level up four times before killing him
Completed the mission "Shoot This Guy in the Face"
Completed the mission "Wildlife Preservation"
Gave Claptrap a high five
Reached level 25
Killed a Chubby
Completed the mission "Bright Lights, Flying City"
Tipped Moxxi $10,000
Completed Round 5 of any Circle of Slaughter
Completed the mission "Rising Action"
Completed the mission "A Train To Catch"
Killed a Constructor without it ever building another bot
Completed 20 side missions
Purchased 5 items from the black market
Completed the mission "A Dam Fine Rescue"
Redeemed 25 tokens
Completed the mission "Hunting The Firehawk"
Unlocked 10 customization items
Completed the mission "Plan B"
Reached level 10
Completed the mission "The Road To Sanctuary"
Completed the mission "Best Minion Ever"
Reached level 5
Revived someone from "Fight for Your Life!" that is on your friends list
Completed the mission "My First Gun"
Complete level 1 of all non-level-specific challenges with a single character
Kill 100 enemies with the Sabre turret
Phaselock 100 enemies
Gunzerk continuously for 90 seconds
Get an item from Michael Mamaril
Hidden
Complete all side missions
Collect 10 pictures of Moxxi in Campaign of Carnage
Completed the mission "Paradise Found".
Defeated the Dark Web.
Allowed Tiny Tina to arm the moonshot cannon.
Activated the Backburner's firewall.
Defeat Haderax the Invincible.
Equip effervescent-quality gear in all slots (except class mod).