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