the difficalty does'nt matter the strategy is still the same, you asked how he did it & I just showed you how.
That's how you do the escort mission on all difficaltys not just nightmare, you go ahead of the Zeplin so it does'nt get bombarded by the balistas.
you summon your wyvern ally to take some of the pressure off you.
You only use the Nuke spell on clusters.
If you were to stay with the Zeplin you'll fail every time because the Zeplin will take too much damage & it won't survive the final stretch.
