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