Press Right, Left, Square(2), Triangle, R3 at the main menu.
Cheat mode
Enter the code at the main menu:
Code
Effect
Square, Triangle, Square, Square, Square, L3
Lisa's costumes and trophies
Clichés
1. Double Jump (found in The Land of Chocolate)
2. Wooden Crate (found in Bartman Begins)
3. Pressure Pads (found in Bartman Begins)
4. Temporary Power Up (found in Around the World in 80 Bites)
5. Combo Punch (found in Around the World in 80 Bites)
6. Giant Saw Blades (found in Lisa the Tree Hugger)
7. Explosive Barrel (found in List the Tree Hugger)
8. Invisible Barrier (found in Mob Rules)
9. Cracked Up (found in Mob Rules)
10. Rift Portal (found in Enter the Cheatrix)
11. Switches and Levers (found in Enter the Cheatrix)
12. Collectible Placement (found in Invasion of the Yokel-Snatchers)
13. Obvious Weakness (found in Shadow of the Colossal Donut)
14. Can't Swim (found in The Day of the Dolphin)
15. Chasm Death (found in Bargain Bin)
16. Time Trial (found in Bargain Bin)
17. Lame Tutorials (found in Game Engine)
18. Trampolines (found in Medal of Homer)
19. Escort Mission (found in Medal of Homer)
20. Enemy Spawners (found in NeverQuest)
21. Infinte Ledge Hang (found in Grand Theft Scratchy)
22. Lava (found in Big Super Happy Fun Fun Game)
23. Flying Boat (found in Big Super Happy Fun Fun Game)
24. Elemental Enemies (found in Big Super Happy Fun Fun Game)
25. Key Card (found in Game Engine)
26. Evil Genius (found in Five Characters in Search of an Author)
27. Re-Used Enemies (found in Game Over)
28. AI Running into Walls (found in Springfield)
29. Steep Slope Barrier(found in Springfield)
30. The Doors (found in Springfield)
31. Collecting Every Cliché
Homer's costumes and trophies
Press Left, Right, Triangle(2), Square, L3 at the main menu.
Infinite Power
Head to the extras section of the main menu and insert the following code, which will give each of your characters infinite power: Circle, Left, Right, Circle, Square, L1.
Marge's costumes and trophies
Press Triangle, Square, Triangle(2), Square, R3 at the main menu.