To be honest, the 2nd mission is the most difficult. The AI is already tough, and with the mod, it's even more challenging. It's good that the campaign even works with the Heroes 5 Armageddon's Blade mod.
Well, nothing surprising really.
The mod doesn't have any scripts, except for the modified .Exe file from Deflaktor, so basically everything is the same as in the vanilla game, except for the content, which is much more abundant.