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