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