Various cheats
     Pause the game, and enter the following codes:

Code:                             Effect:
X, Down, Down, Up, Left, Right    Faster Build-Up
X, Left, Right, Up, Left          Get $10,000 Instantly
X, Right, Right, Left, Up         Get 100 Population Instantly
X, Up, Up, Left, Right, Left      Get access to all missions in Replay Mode
Right, Left, Right, Right, and X  Invincible Units

     Hold  all  4  shoulder buttons then press X, Up, Up, Left, Right,
Left - Level Skip

Level Skip Note:
     Repeat  this  code  until  the confirmation message appears. Then
quit  your  game and when you get debriefed, press X to advance to the
next mission.