Game: Destroy All Humans! Big Willy Unleashed, Platform : PSP Game Cheat Codes
Unlockable: Furon Invasion
After you complete the last mission you can go to Harbour city or Vietmahl, you will have
to find a small yellow marker and walk into it to start the invasion.
In Harbor City, the marker is hidden under one of the crates in the harbor behind big
Willy's restaurant.
In Vietmahl, the marker is in the military encampment behind the ruins.