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