Here is the full list of all 80 Borderlands: Game of the Year Edition achievements worth 1,750 gamerscore.
Completed each of the larger challenges in all 3 coliseums
Completed the larger challenge in The Angelic Ruins coliseum
Killed 15 enemies with the Berserker's action skill
Killed an enemy with the Siren's action skill
Completed a crazy request for Tannis
Completed all missions in Secret Armory
Killed each of the loot midgets
Killed 15 enemies with the Hunter's action skill
Played with at least two other players.
Paid for a worthless tour of the world's largest bullet
Killed the Interplanetary Ninja Assassin Claptrap
Killed Commandant Steele-trap
Killed Dr. Ned-trap
Killed General Knoxx-trap
Emerged victorious from an arena match
Killed an enemy plumber-style
Killed the Vault Boss
Completed all missions in the Rust Commons
Discovered Eridian Promontory
Discovered Crimson Lance Enclave
Rescued enough Claptraps to earn 42 inventory slots
Killed Flynt
Killed the Rakk Hive
Rescued a groupmate from death in a co-op game
Reached Level 61
Reached Level 51
Earned level 50
Killed Crawmerax the Invincible
Destroyed Lance Depot
Earned level 40
Destroyed a Lancer while in a Racer
Rescued Athena
Built the New Car: Monster
Discovered Trash Coast
Earned level 30
I bet you never thought you'd be here
Raced around the Ludicrous Speedway in record time
Killed Krom
Discovered Krom's Canyon
Completed 5 missions in the Rust Commons
Discovered The Scrapyard
Reached proficiency level 10 with any weapon type
Completed all missions in the Arid Badlands
Completed the larger challenge in the Hell-Burbia coliseum
Earned level 20
Defeated the Rakk Hive, the Vault Boss, Sledge, Krom, or Flynt in a co-op game
Killed Sledge
Discovered Headstone Mine
Applied an elemental artifact
Equipped a class mod for your character
Completed the larger challenge in The Gully coliseum
Completed the lesser challenge in all 3 coliseums
Completed 15 missions in co-op
Killed 25 enemies by ramming them with any vehicle
Killed 15 enemies with the Soldier's action skill
Earned level 10
Killed 5 Rakk in under 10 seconds
Discovered Skag Gully
Earned level 5
Completed 5 missions in the Arid Badlands
Won a duel without taking damage
Won a duel against another player
Discovered Sledge's Safe House
Killed 25 enemies with explosive weapons
Killed 25 enemies with shock weapons
Killed 25 enemies with incendiary weapons
Killed 25 enemies with corrosive weapons
Mastered the technology of Pandora
Earned $1,000,000
Sold 50 guns to a shop
Completed the "Braaaaaaaaaaaaains!" mission
Killed Ned. Again.
Killed Ned...sort of
Completed the "Jakobs Fodder" mission
Completed the "House of the Ned" mission
Collected 3 panties, 5 fish in a bag, and 15 pizzas
Collected 5 3D glasses
Collected 15 Claptrap bobbleheads
Found 25 oil cans
Found all 6 Claptrap statues