Brutal Legend -
The Metal Beasts can breath fire unleashing a ton of damage upon any nearby Drowning Doom units. About half-way through this mission you'll come across a road block that the convoy can't pass. Navigate around this blockade by yourself until you get behind it. Notice the rope that is holding this road block in place. Walk up to and attack the rope so that the blockade is removed, allowing the convoy to continue to the next waypoint.