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