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