Unlimited Armor
Go to the main menu and press and HOLD Z and press Up, Right, Down, Left

Unlimited Ammo
Go to the main menu and press and HOLD Z and press L, R, L, R

Select Level
Go to the main menu and press and HOLD Z and press C-Up, C-Right, C-Down, C-Left, Start

Get Free Satellite
Go to the main menu and press and HOLD Z and press B, C-Left, C-Down, A

Get Free Buildings
Go to the main menu and press and HOLD Z and press A, B, A, B

Speed up game
Hold Z and R and press any C button, at main menu