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