Hispaniola two-part is fun even if you are well prepared, and indeed quite difficult. Good stuff.
Defending your fortress is incredibly easy, it's one of the easiest 'big' battles. By that time you should have saved up plenty of items, so you park your men in the entrance, set up the cannon two or three spaces behind, set other items as necessary. E.g. you can use barricades to make a narrow bottleneck then lantern + cannon away, or in my latest playthrough, I had so many spike traps without trying I set 15 in a cone and they triggered 14 of them.
Moctezuma isn't a cakewalk like that one, but it would have been harder if you weren't attacking from a narrow corridor. Even though you are the one attacking a beleaguered enemy, you start in a bottleneck and then they all rush into that narrow corridor. You can't prepare, but if you have lanterns and a couple of high defense, well equipped warriors...
I just wish they maximised the potential of this game by tweaking the encounters a little bit. There are a few interesting designs that significantly impact your tactics (e.g. if you attack Esteban in the mine without luring into an ambush), but too often the combination of (1) encounter design that doesn't matter, (2) enemies that rush at you most of the time means most battles can be won using similar tactics. The causeway battles, either side you're on, are nonsense because of this.
E.g.: situations where enemies are defending and won't come out, and you have to smoke them out somehow, and you lose if you don't win within x turns - this would have worked very well with a few of the existing set pieces. With the fortress, it would have been lovely to actually defend from the fortress itself, but I imagine that might have required a lot more work... well, at least you could have started with barricades instead of fences so that they are destructible, and 50% more natives, and natives that actually come at you in a single wave instead of half of them straggling behind so their comrades are all dead by the time they arrive.
