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