Here are some cheats and tips for the game Guerrilla War.
Level and difficulty selection:
Select a one or two player game, then hold A or B
and press Start to begin game play. Alternatively, hold
A + B and power on the NES. Continue to hold those
buttons and press Start(2).
Continue game play:
Hold A + B immediately after the game over screen
appears.
Options:
Press Select + Start + B at the player
number selection screen. Press Up or Down to select
an option, press A to change the current option, and press
Start to begin game play.