You complete Mission 5 when u have defeatet 2 Bosses.The First u met far down in the center of the machine carlos is working with.U have to kill him in order to stop him.Destroy the surrounding Generators by shooting at their topcaps with hellpower.The floating soldiers are your mana sources, so kill them.When the machine is gone he´s quite angry and changes to his true form.Don´t worry,Black sends u Infernal Markers from time to time in order that u can replenish your mana while u r shooting at Carlos with hellpower.After a while he will die and another challenge awaits,
The fight before, Black helps u killing Carlos,now he´s on the other side and tries to eliminate you.But it´s quite simple.Shoot him with your best normal weapon until he´s going to his knees.Then move quick to a yellow flashing panel,press the button and quickly run up the way u came down before the first fight.Opposite of the first door on the right u met there is a catwalk.Go there and at its end u press another button.The machine rises.Walk down and fight Black 2 other times and repeat this scheme.When u run short of health,there r healthboxes everythere.Look for them and use them.He´is about to die then and u have beaten this game!Congratulations!