In the last part of the game when you are in hoxies office battleling those 2 red robots.

Take my advice and use the darn mimi gun then the shotgun it is right by the shot gun take my advice do not use stratagy guids advice unless you want to die a painful death.

When you do have the mini gun hold the R trigger like you never have and before you know it the cloaking devices will be deactivated and walla you beat the game.