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