Complete the indicated task to unlock the corresponding stage. Note: Levels must be unlocked separately for each Extra Content type (Mercenaries, Siege, Predator, etc.)

Stage	How to unlock
Stage 4: Rail Yard	Complete Mining the Depths with a "B" rank.
Stage 5: High Seas Fortress	Complete Rail Yard with a "B" rank.
Stage 6: Catacombs	Complete High Seas Fortress with a "B" rank.
Stage 7: Requiem for War	Complete Catacombs with a "B" rank.
Stage 8: Liquid Fire	Complete Requiem for War with a "B" rank.
Stage 9: Rooftop Mission	Complete Liquid Fire with a "B" rank.
Stage 10: Creature Workshop	Complete Rooftop Mission with a "B" rank.