This will take a while so if you ether don't have patence or just don't care that much than I suggest not using this tip. This for only the challenges that require you to find things in buildigs. First, look throgh the buildings for the items. Then record where you saw them & just replay the challenge.
(Another tip:The items are always in the same place as before.)
Unlock Bubba by getting all 29 characters.
Unlock Eyegore by Completeing all the challenges for every city.
Unlock Philbert by getting the Par Score Star for each city.
to get the cheat code screen up, hold R2 and L2 at the main menu. You will hear a sound when you enter a code correctly
then use these codes:
Unlock All Monsters= 141421
One Hit Building Destruction= 071767
No Damage from the military= 986960
View Opening Movie= 667300
View Ending Movie= 667301
View Credits= 667302
Display Version Number= 314159
Reset all Cheats= 000000