Metal Slug 2006 Cheats for PlayStation 2
At the 'Garage' menu select 'Laboratory' mode and during the missions collect the CDs to unlock the laboratory staff.
Unlock the Extras Menu:
Complete Story (Marco's) mission to unlock the completion extras which includes Colour Edit, Movies, BGM Test and a Mini Game.
Unlock Unlimited Monolith (Sub-Weapon):
Complete Story (Marco's) mission.