LEGO Star Wars II: The Original Trilogy (X360)

Achievements
Bespin
Complete Bespin without dying.

Bounty Hunter missions complete
Complete all of the Bounty Hunter Missions.

Carkoon
Complete Carkoon without dying.

Character & Vehicle Bonuses
The character and vehicle bonuses are all too easy if you know what you're doing. First off, you shouldn't have been spending money on buying any character in the store, since you unlock (for free) one character type (Imperial, Bounty Hunter, Midget Character) when you complete all the stories.

Secondly, you need to save up $900,000 and buy the Power Block Invulnerability. You can unlock that crucial block by locating it in Free Mode in Episode 4 Chapter 5. Once you leave the trash compactor, open the first "locked" door you find (it's a second trash compactor room). Investigate that room for your much needed cheat block.

Now you have the right tools (i.e., invulnerability), you can stick to using a bounty hunter and simply lob Thermal Detonators to blow up masses of enemies as well as the shiny metal objects that leave the $10,000 purple stud in the stages (for vehicle stages, some objects destroyed leave a purple stud). These objects (in character and vehicle stages) regenerate, so you basically "run a loop" blowing up the objects you destroyed and coming back to them later.

Lastly, if you have Jango Fett (PS2, Cube, and Xbox only) or bought Boba Fett, they are a good character to have on Episode 5's character bonus level, since they can simply jet pack over the gaps in Bespin. For the most part, you can jump (once) with any Blaster using character and shoot while moving to kill enemies and pick up studs. For $1 million, the blue studs don't count much (although grab them if they are in a pile), so go for the very rare purple studs extracted from destroyed objects.

Cloud City Trap
Complete Cloud City Trap without dying.

Crushing the Rancor's Little Skull
In the end of Episode 6: Jabba's Palace, you have to beat the Rancor. First, activate the panel on the right or left side. This will cause a Gamorrean Guard to drop out from the enemy producing tubes.

Let the Rancor grab the enemy and it will walk to a corner to eat. Pull the switch next to the rancor and an explosive box (shoot it to blow it) will drop down. This explosive is the only way to damage the rancor.

Drop in another Gamorrean Guard to repeat the process. This time, the rancor will walk to a different corner but a similar switch for the explosive box will be present.

Repeat the Gamorrean Guard drop for a third time and the rancor will walk to the door where it came out from. Use the non-droid characters to pull both switches by the door to defeat the rancor once and for all.

Dagobah
Complete Dagobah without dying.

Death Star Escape
Complete Death Star Escape without dying.

Death Star II
Complete Death Star II without dying.

Destroy AT-ATs
The AT-ATs are indestructable until you trip them using the tow cable. Once they are downed, tow a bomb from a bomb dispenser and blow it up. AT-ATs that are downed will revive like a Hammerite Undead from Thief Dark Project if enough time elapses.

Different Characters
Enter the following password to unlock the characters for purchase in Free Play Mode.

Password - Effect
NAH118 - Unlock Greedo
JAW499 - Unlock Jawa
YDV451 - Unlock Sandtrooper
PEJ821 - Unlock Tusken Raider

Double Score Zone Exploit
Double score zones allow players to gain double the credits from studs. Because of that weird effect, you can exploit it by killing your partner (2 active players only) and taking his money (and vice versa). While you lose a set amount of money, you also gain double that amount because of the double scoring effect.

Echo Base
Complete Echo Base without dying.

Endor
Complete Endor without dying.

Episode IV complete
Complete all six levels in this Episode in Story Mode.

Episode V complete
Complete all six levels in this Episode in Story Mode.

Episode VI complete
Complete all six levels in this Episode in Story Mode.

Facon Flight
Complete Facon Flight without dying.

Game 100% complete
Complete everything in the game.

Game 20% complete
Complete 20% of the game.

Game 40% complete
Complete 40% of the game.

Game 60% complete
Complete 60% of the game.

Game 80% complete
Complete 80% of the game.

Hoth Battle
Complete Hoth Battle without dying.

Jabba's Palace
Complete Jabba's Palace without dying.

Jedi Destiny
Complete Jedi Destiny without dying.

Jundland Wastes
Complete Jundland Wastes without dying.

LEGO City complete
Complete the LEGO City level.

Lego Spigot
Once you have unlocked all 99 gold bricks by getting all the minikits, true jedi on every level on free play, story and you have done all the bounty hunter missions and the bonuses in each chapter, you can head outside of the cantina. Walk around until you find the pile of gold bricks, build them and then you will have an unlimited supply of lego studs. This is very useful for unlocking everything in the cantina.

Mos Eisley
Complete Mos Eisley without dying.

Rebel Attack
Complete Rebel Attack without dying.

Rescue the Princess
Complete Rescue the Princess without dying.

Secret Plans
Complete Secret Plans without dying.

Secret Plans level complete
Complete the first level of the game.

Speeder Showdown
Complete Speeder Showdown without dying.