Das Geisterschiff

Das Geisterschiff is a turn-based cyberpunk adventure/dungeon crawler hybrid with survival horror elements where you play as a mecha pilot working for one of the megacorps.
By 2072 the Earth turned into a scorched wasteland, forcing the population to move underground while two megacorps are stuck in an endless war over the territory and resources. After graduating from the military academy you've decided to join one of them.