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