Full list of all 80 Borderlands achievements. It takes around 50-60 hours to unlock all of the achievements in the base game on Windows.
The base game contains 50 achievements, and there are 4 DLC packs containing 30 achievements.
Rescued enough Claptraps to earn 42 inventory slots
Killed 15 enemies with the Soldier's action skill
Killed an enemy with the Siren's action skill
Killed 15 enemies with the Berserker's action skill
Gamed with fame
Defeated the Rakk Hive, the Vault Boss, Sledge, Krom, or Flynt in a co-op game
Completed 15 missions in co-op
Emerged victorious from an arena match
Rescued a groupmate from death in a co-op game
Won a duel against another player
Won a duel without taking damage
Mastered the technology of Pandora
Earned level 40
Completed all missions in the Arid Badlands
Killed the Vault Boss
Discovered Eridian Promontory
Discovered Crimson Lance Enclave
Killed Flynt
Killed the Rakk Hive
Discovered Trash Coast
Earned level 30
Killed Krom
Discovered Krom's Canyon
Earned $1,000,000
Reached proficiency level 10 with any weapon type
Killed 25 enemies with corrosive weapons
Completed 5 missions in the Rust Commons
Killed an enemy plumber-style
Killed Sledge
Earned level 20
Discovered The Scrapyard
Discovered Sledge's Safe House
Discovered Headstone Mine
Equipped a class mod for your character
Killed 15 enemies with the Hunter's action skill
Killed 25 enemies with explosive weapons
Applied an elemental artifact
Sold 50 guns to a shop
Completed 5 missions in the Arid Badlands
Earned level 5
Earned level 10
Discovered Skag Gully
Killed 25 enemies by ramming them with any vehicle
Killed 5 Rakk in under 10 seconds
Killed 25 enemies with shock weapons
Killed 25 enemies with incendiary weapons
Completed all missions in the Rust Commons
Raced around the Ludicrous Speedway in record time
Earned level 50
I bet you never thought you'd be here.
Completed the "Braaaaaaaaaaaaains!" mission
Killed Ned. Again.
Killed Ned...sort of
Completed the "House of the Ned" mission
Completed the "Jakobs Fodder" mission
Reached the end of the larger challenge in The Angelic Ruins coliseum
Reached the end of each of the 3 larger challenges with one character
Reached the end of the larger challenge in the Hell-Burbia coliseum
Reached the end of the larger challenge in The Gully coliseum
Completed the Prove Yourself mission
Destroyed the Lance Depot
Destroyed a Lancer while in a Racer
Rescued Athena
Built the New Car: Monster
Killed Crawmerax the Invincible
Killed each of the loot midgets
Reached Level 51
Reached Level 61
Completed all missions in Secret Armory
Paid for a worthless tour of the world's largest bullet
Read all 6 claptrap statue placards
Collected 3 panties, 5 fish in a bag, and 15 pizzas
Collected 15 claptrap bobbleheads
Found 25 claptrap oil cans
Completed Tannis' crazy request
Collected 5 3D glasses
Defeated the Interplanetary Ninja Assassin Claptrap
The Commandant is dead-trap
Killed Ned... again and again and again
Knoxx is at rest...finally