Here is the full list of all 42 LEGO Star Wars: The Complete Saga achievements worth 1,000 gamerscore.
Finish Episode III in story mode
Destroy 5 people with one attack (Jedi super slam).
Destory 300 droids.
Finish Episode II in story mode.
Perform 200 perfect lightsaber deflections.
Finish Episode I in story mode.
Finish Episode IV in story mode.
Finish Episode V in story mode.
Finish Episode VI in story mode.
Unlock all characters.
Collect all available red bricks.
Collect all available Gold Bricks.
Collect all mini-kits.
Complete the game to 100%
Perform 20 unblockable combo attacks.
Perform 200 blaster character dodges.
Destroy 300 stormtroopers.
Destroy 50 TIE fighters.
Ride all mounts types & ride-ons.
Sell your landspeeder to the Jawas.
Break Jar Jar 20 times.
Disable 5 Droidikas with R2D2.
Destroy 10 characters with one thermal detonator.
Pull 25 arms off other characters.
Set off all three Discos.
Death Star Trench Run without Firing.
Start a Cantina Fight with 50 casualties.
Make 100 Build-its throughout the game.
Max out the stud counter.
Finish Cloud City still wearing a Helmet.
Wear Every Hat.
Crossover: Destroy Anakin with Vader.
Crossover: Destroy Jango Fett with Boba Fett.
Crossover: Destroy The Emperor with Darth Maul.
Revenge: Destroy The Emperor with Mace Windu.
Revenge: Destroy The Emperor with Kit Fisto.
Revenge: Destroy Anakin with Dooku.
Revenge: Destroy Darth Maul with Qui-Gon.
Revenge: Destroy Darth Vader with Obi-Wan.
Get 100 points in Arcade Mode
Play through an entire level online
Shoot First