Various cheats
  
Cheat menu:
     At  the  main  menu,  press and hold L2, Circle, R2 in that order
then  let go of Circle, R2, L2 in that order. Then enter the following
cheat codes.

Cheat code:             Result:
246518                  Master code
659996                  Unlock All Cities
525955                  Unlock All Monsters
975013                  Unlock Challenges
122574                  Energy doesn't regenerate
532459                  Get 100,000 Points
667596                  Get 150,000 Points
750330                  Get 200,000 Points
536117                  Health Regenerates
812304                  Buildings are indestructible
259565                  Player 1 deals 4x damage
819342                  Player 1 has Infinite Energy
531470                  Player 1 is Invisible
338592                  Player 1 is Invulnerable
927281                  Player 2 deals 4x damage
324511                  Player 2 has Infinite Energy
118699                  Player 2 is Invisible
259333                  Player 2 is Invulnerable
500494                  Player 3 deals 4x damage
651417                  Player 3 has Infinite Energy
507215                  Player 3 is Invisible
953598                  Player 3 is Invulnerable
988551                  Player 4 deals 4x damage
456719                  Player 4 has Infinite Energy
198690                  Player 4 is Invisible
485542                  Player 4 is Invulnerable
294206                  Unlock Gallery 1
409014                  Unlock Gallery 2