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