Here is the full list of all 80 Borderlands: Game of the Year Edition achievements worth 1,750 gamerscore.
Defeated the Rakk Hive, the Vault Boss, Sledge, Krom, or Flynt in a co-op game
Completed 15 missions in co-op
Collected 3 panties, 5 fish in a bag, and 15 pizzas
Killed 15 enemies with the Berserker's action skill
Killed 15 enemies with the Hunter's action skill
Killed 15 enemies with the Soldier's action skill
Raced around the Ludicrous Speedway in record time
Collected 15 Claptrap bobbleheads
Reached Level 61
Reached Level 51
Killed each of the loot midgets
Found all 6 Claptrap statues
Completed all missions in Secret Armory
Earned level 50
Paid for a worthless tour of the world's largest bullet
I bet you never thought you'd be here
Emerged victorious from an arena match
Rescued a groupmate from death in a co-op game
Won a duel without taking damage
Won a duel against another player
Completed the lesser challenge in all 3 coliseums
Completed the larger challenge in The Gully coliseum
Completed each of the larger challenges in all 3 coliseums
Destroyed a Lancer while in a Racer
Killed Crawmerax the Invincible
Destroyed Lance Depot
Rescued Athena
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
Completed the larger challenge in The Angelic Ruins coliseum
Killed the Rakk Hive
Discovered Trash Coast
Earned level 40
Completed the "Braaaaaaaaaaaaains!" mission
Killed Ned. Again.
Killed Ned...sort of
Completed the "Jakobs Fodder" mission
Completed the "House of the Ned" mission
Built the New Car: Monster
Found 25 oil cans
Killed the Interplanetary Ninja Assassin Claptrap
Killed Commandant Steele-trap
Killed Dr. Ned-trap
Killed General Knoxx-trap
Earned level 30
Completed the larger challenge in the Hell-Burbia coliseum
Played with at least two other players.
Killed Krom
Discovered Krom's Canyon
Completed a crazy request for Tannis
Earned $1,000,000
Killed 25 enemies with shock weapons
Collected 5 3D glasses
Killed 25 enemies with corrosive weapons
Discovered The Scrapyard
Reached proficiency level 10 with any weapon type
Completed 5 missions in the Rust Commons
Mastered the technology of Pandora
Completed all missions in the Arid Badlands
Killed an enemy plumber-style
Earned level 20
Equipped a class mod for your character
Killed Sledge
Killed 25 enemies by ramming them with any vehicle
Applied an elemental artifact
Killed an enemy with the Siren's action skill
Discovered Sledge's Safe House
Killed 25 enemies with incendiary weapons
Sold 50 guns to a shop
Earned level 10
Killed 5 Rakk in under 10 seconds
Discovered Skag Gully
Earned level 5
Killed 25 enemies with explosive weapons
Completed 5 missions in the Arid Badlands
Discovered Headstone Mine