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