The problem I have with 99.9% of the maps is that, ones you've won it, you know what to do. There is no randomness. So you can change it to be more difficult but ones you're figured out how to beat it, it's "easy" again. It took me a couple of tries to figure out what to do, so I guess the difficulty level is fine (I would rate it as Very Hard, especially winning the first try)
I noticed I had to be on guard every second of the game, I like that and I don't like that at the same time, cause it gets tiresome after a while. I surely wouldn't want a 20 map campaign this way lol. In my opinion(!) there should be some pauses where you can clean up the mess and get yourself back in the saddle.
But as I said, I'm more of a turtling player, who likes to be safe and charge a door ones I feel it's time to do that.
It surely is more fun and challenging than the Original Campaign.