UnMetal

In 1972 a crack commando unit threw you in prison for a crime you didn't commit. You promptly escaped from a maxumum-security stockade to the underground trying to survive from these soldiers of fortune.
UnMetal is a 2D stealth/action game (with a bit of humor) where the goal is to escape from an enemy military base. But what started as a simple break out ended up being an inside operation to prevent a massive attack against the NATO.