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