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