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