Tiny Tina's Assault On Dragon Keep: Dark Souls easter egg:
The "Lost Souls" side quest contains many references to Dark Souls. An undead hero named "Crestfallen Player" is waiting near a bonfire and states that he's died "eighty times" and another player keeps invading his game to steal his souls. Once the souls are retrieved a glowing red knight named "-=n00b_killer=-" will appear. Kill him and the Crestfallen Player will say that "-=n00b_killer=-" repeatedly backstabbed him while he drank from his flask. Once the side quest is over, he says "It can be hard out here on Pandora. You'd better hold onto your humanity as best you can."
Tiny Tina's Assault On Dragon Keep: A Game Of Thrones easter egg:
Begin the "Winter Is A Bloody Business" quest, which sets you out to defeat an evil prince named "Jeffrey", a reference to Joffrey. Defeat the guards in a throne room that resembles the one in King's Landing, two guards named "Canine" and "Molehill", a reference to the Hound and the Mountain.
Easy Thousand Cuts farming:
Accept the quest "Rocko's Modern Strife" and go to Thousand Cuts to start "Defend Slab Tower". You should notice that no foes will spawn in the area as long as you don't progress through the quest. Since normal foes will no longer spawn, you are free to circle the area and loot every chest without being hindered by enemies. However, foes such as one-armed bandits and loot midgets will still spawn. If you save and exit after clearing all the chests, you can just accept "Defend Slab Tower" once again and clear them out as many times as you like with the same conditions as long as you don't complete the quest.
Easy "Not Full Of Monkey" challenge leveling:
"Not Full Of Monkeys" is a challenge that invloves killing enemies with stationary barrels of any type. With Gaige the Mechromancer DLC, you don't need the barrel! Anger a swarm of Rakks and summon the Deathtrap. When they rush you, the Deathtrap will use its laser to kill them. It counts as a stationary barrel this way. Try this on flying enemies for some quick Badass rank.
Carry one more item in your backpack:
Two class mods are needed for this to work. When your backpack is full, switch your currently equipped class mod for another one in your backpack (you can then re-equip your original class mod after doing this). Then, exit the backpack menu. You can now pick up one more item and have a backpack with 28 items in it instead of maximum 27.
True Vault Hunter mode:
Complete Normal difficulty story mode to unlock the True Vault Hunter mode.
Enter the Konami code at the title screen: UP(2), DOWN(2), LEFT, RIGHT, LEFT, RIGHT, B, A, START. This will unlock Extra Wubs in the gameplay part of the options menu. Extra Wubs literally does nothing.
Harvest Golden chest:
A thumb drive or a Playstation plus membership is required. Back up a save file to either one and then do the following:
1. Load a two player game with the second player having a golden key (and being the save file backed-up to either thumb drive or Playstation plus cloud.)
2. Open the chest with second player, then take the chest contents and give it to player one.
3. Save and quit game, then Exit Game.
4. Copy the backed up save file to hard drive. Player one save file will have chest contents and player two will have the key back. Repeat as many times as desired.
In the Tundra Express, complete all the optional quests for Tiny Tina that lead up to "You Are Cordially Invited: RSVP". This quest requires you to lure Flesh-Stick into Tiny Tina's cave so that she can put him in a trap. The trick is to just kill him. Depending on what level you are (Level appropriate on first playthrough is anywhere from 1800-3000 exp per kill, playthrough 2 is anywhere from 2000-4500 per kill). After you kill Flesh-Stick, simply go back to Tiny Tina and restart the quest. If you are online and playing with friends, just have 1 friend stand by Tina while someone else stays by Flesh-Stick's spawn, and he will pop up instantly each time.
First, place the desired item(s) on a character, then ready or create a second character to take on as many of the item as you want. Start a two-player co-op game with the first character as player 1 (and the other character as player 2, obviously), then give the desired item(s) to player 2. Have player 2 save and leave game, then quit the game through the PS3 system menu. Since the game doesn't save player 1 when player 2 leaves nor when you quit from the system menu, both players will then have said item(s). Repeat as desired (for faster duplication, transfer all copies of the item to player one, save-and-quit with both, then start over with the duplicates on player 1).
Badass Rank farming:
To build a high Badass Rank and earn all the perks associated with it, make a pair of new characters in co-op mode and have player 1 beat player 2 in 50 duels. This offers 166 Badass Ranks. Save and quit, then start another new game, creating another new character for player 1 (leave player 2's character alone). Fight another 50 duels with player 1 winning them all for 166 more Badass Ranks. Repeat as desired, and delete the pile of unwanted characters when you're done. If you set the controller configuration to something where you can just keep tapping the melee-attack button without ruining your aim at the other player, you can end a duel-run like this in roughly 10 minutes. So in one hour you can build up 996 Badass Ranks.
Easy leveling hint:
Once you complete the quest "A Dam Fine Rescue", you will find Sir Hammerlock inside Sanctuary offering a quest called, "Mighty Morphin'" that involves taking an Injector and injecting Varkid Cocoons with a special serum. Injecting the serum into a cocoon forces a huge flying Badass version of a Varkid. Killing one yields 1,900 Experience. If you don't complete or turn-in the quest you can wipe the entire zone of cocoons, save the game, reload, and repeat.
To unlock characters skin from the original game, have a saved game file from the original Borderlands.
Minecraft easter egg:
At the Sanctuary Hole after Chapter 9, jump off a cliff and go to Caustic Caverns. Run northwest to Guardian Ruins then go to the minecarts and turn right. Jump over the rectangular rocks and turn left to find Minecraft dirt. Break though it to reach Minecraft stone, cobblestone, and coal. Break though those to find Creepers along with blocks of gold, diamond, iridium and more. Kill the Badass Creeper to unlock Minecraft-themed skins (Steve Head, Steve's Clothes etc.).
Fast secondary character leveling hint:
Once you reach Tiny Tina do all of her side missions until you make it to the final stage of her tea party. Here she wants you to lure Flesh-Stick to her little cove to join her tea party. Since you can fail this mission by killing him, you can actually repeat it. If you have a second controller and another character, have that created person join your session and have them run all the way to Tiny Tina. If you keep them in front of her and your main character in front of where Flesh-Stick walks out you can kill him and re-accept the mission as fast as your trigger finger allows, making anyone reach about level 20-21 in a matter of minutes.
Goliath, Meet David - Allowed a Goliath to level up four times before killing him.
Went Five Rounds - Completed Round 5 of any Circle of Slaughter.
Not Quite Dead - Reached level 5.
Better Than You Were - Reached level 10.
Arctic Explorer - Discovered all named locations in Three Horns, Tundra Express, and Frostburn Canyon.
Urban Explorer - Discovered all named locations in Sanctuary, Opportunity, and Lynchwood.
Highlands Explorer - Discovered all named locations in The Highlands, Thousand Cuts, and Wildlife Exploitation Preserve.
Blight Explorer - Discovered all named locations in Eridium Blight, Arid Nexus, and Sawtooth Cauldron.
Sugar Daddy - Tipped Moxxi $10,000.
Decked Out - Had Purple-rated gear or better equipped in every slot.
Sabre Rattler - Killed 100 enemies with the Sabre turret.
Phased and Confused - Phaselocked 100 enemies.
So Much Blood! - Gunzerked continuously for 90 seconds.
Cute Loot - Killed a Chubby.
Tribute To A Vault Hunter - Got an item from Michael Mamaril.
Definitely An Italian Plumber - Killed Donkey Mong.
High-Flying Hurler - Killed a flying enemy with a thrown Tediore weapon.
Token Gesture - Redeemed 25 tokens.
Unseen Predator - Remained in Zero's Deception mode for ten seconds straight.
Build Buster - Killed a Constructor without it ever building another bot.
How Do I Look? - Unlocked 10 customization items.
Friendship Rules - Revived someone from "Fight for Your Life!" that is on your friends list.
Better Than Money - Purchased 5 items from the black market.
Up High, Down Low - Gave Claptrap a high five.
Bounty Hunter - Completed 20 side missions.
First One's Free - Completed the mission "My First Gun".
Dragon Slayer - Completed the mission "Best Minion Ever".
A Road Less Traveled - Completed the mission "The Road To Sanctuary".
New In Town - Completed the mission "Plan B".
An Old Flame - Completed the mission "Hunting The Firehawk".
No Man Left Behind - Completed the mission "A Dam Fine Rescue".
Wilhelm Screamed - Completed the mission "A Train To Catch".
Sky's The Limit - Completed the mission "Rising Action".
Can See My House From Here - Completed the mission "Bright Lights, Flying City".
Farewell, Old Girl - Completed the mission "Wildlife Preservation".
Got The Band Back Together - Completed the mission "The Once and Future Slab".
What does it mean? - I can't even capture it on my camera.
Well That Was Easy - Completed the mission "Shoot This Guy in the Face".
Feels Like The First Time - Opened the chest at the bus stop in Fyrestone.
Always Improving - Reached level 25.
Capped Out…For Now - Reached level 50.
World Traveler - Discovered all named locations.
Did It All - Completed all side missions.
Identity Theft - Completed the mission "The Man Who Would Be Jack".
An Angel's Wish - Completed the mission "Where Angels Fear To Tread".
Bombs Away - Completed the mission "Toil And Trouble".
Knowing Is Half The Battle - Completed the mission "Data Mining".
Thresher Thrashed - Defeated Terramorphous the Invincible.
Challenge Accepted - Completed level 1 of all non-level-specific challenges with a single character.
Cool Story, Bro - Defeated Jack.
Borderland Defender Round Two - Unlocked all Borderlands 2 trophies.
"Captain Scarlett And Her Pirate's Booty" trophies:
Gadabout - Discovered all named locations in Oasis and the surrounding Pirate's Booty areas.
Completionist - Completed all Pirate's Booty side missions.
Treasure Hunter - Completed the mission "X Marks the Spot".
"Mr. Torgue's Campaign Of Carnage" trophies:
Explosive - Completed the mission "Long Way To The Top".
Motorhead - Completed all Campaign of Carnage side missions.
Obsessed - Collected 10 pictures of Moxxi in Campaign of Carnage.
"Sir Hammerlock's Big Game Hunt" trophies:
Face Off - Completed the mission "The Fall of Nakayama".
Been There - Discovered all named locations in Hammerlock's Hunt.
Done That - Completed all Hammerlock's Hunt side missions.
"Tiny Tina's Assault On Dragon Keep" trophies:
I Totes Planned That Boss - Slew Mister Boney Pants Guy.
Yaaaaaay - Introduced thyself to the White Knight.
Girl's Gotta Eat - Fed thy noble queen 3 times during one visit to her quarters.
It's Like That One Video - Showed thine worst enemy, the abomination known as "The Darkness," who is the nerdiest of them all.
They Was All "Hey That's Mine" - Unsheathed 5 swords from Immortal Skeletaurs without leaving the area.
Hmmmmm - Wielded the Mysterious Amulet.
Keep Rollin' Rollin' Rollin' - Demonstrated your skill, or lack thereof, at rolling the magical treasure orb of many sides.
Shorty, You So Best - Completed thy quest by rescuing yonder queen.
Dang Girl You Ace At This Game - Won the most challenging round in Murderlin's Temple.
Make it Raaaaaid - Vanquished the Ancient Dragons of Destruction.