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