It's a great Campaign like the previous ones but it is a bit shorter in my experience but that doesn't deter the fact its fun to play.
Possible Bugs: First mission, I destroyed the Orc base before activating all the Nexuses, This ends the mission immediately by giving a quest I had undiscovered, this wasn't intentional but I went to very far methods to destroy my aggressor before dealing with the rest of the Nexus's (I understand you were supposed to claim the nexuses first but I thought the base as a optional attacker, this also made me miss out on the Nerubian side quest.
Not related to quest/Cheated exlusions: Its not really related to anything at all really but the Orc attackers on the human defences all go the same path due to two of your triggers force the units to go to the same spot the at the "North & South" Checkpoints, I think it was intended to be positioned on the human side so the north and south spawn worked their way to the Bloodelf Lieutenant. To be fair you could just ignore this but I'd like the idea that you had to destroy the demons before the Orcs finished off the human defences as they would then march on you/Demons are then unhindered on the "Border"
Feedback delving the "Harder" difficulties I noticed it was things like "XP handicap" and adding Hardened Skin to every red unit? (On chapter 9 that is anyway)
I understand this might make it... Slightly more difficult but I hope you will find different ways to make harder difficulties a bit more of a AI improvement (Perhaps on hard Orange actually attacks you?)
Either way good Campaign and hardly many noticeable bugs. (And sorry for opening your Campaign map, I just get curious as I used to mapmake myself way back when.)
Update/2nd Playthrough: Actually this probably needs fixing, I didn't notice it earlier but there is dialogue with the humans gradually losing their front lines and Grennan dying when he is quite clearly still alive, At first I thought this was an irrelevant error but it might take a bit out of the feel for Chapter 9, depends on the player wanting to explore though.
Difficulty: There is no change between Easy & Normal, The "Easy Handicap" on health isn't there, Either that or the handicap is different I have currently not seen any change in making it easier than Normal.
Decision/Side Quests, I havn't really noticed as much "choices" as the other two Campaigns, I've noticed the Nerubian in the last chapter but otherwise thats about it, What did destroying the caves do? Possessing Sir Roy.. Royy*? Does he return later? (did I miss him?) Not fullfilling side quests didn't change much, The only one I completed was the Nerubian and I saw no difference by Chapter 9, At the most I was missing a few items, was this intended? Air Superiority - Changed nothing? They don't even attack the imperials anyway so I presume its just for the item? My problem with just the item isn't really a rewarding feeling, I liked the idea that "If I don't kill these people here now then later I will have a positive/Negative effect on the world.
Another problem I have with the Undead is this "Working behind the scenes" agenda, I understand that they don't want to be noticed but in the other campaigns the Orcs were pretty aware of the undead, Even the humans were surely, They met Rahandir in the caves. Even the Guy (forgot name he's supposed to be the Protagonist of the 2nd human book apparently) must know the undead exist. I understand its supposed to be 'humans are ignorant' but losing a few Outpost and Armies constantly and nobody investigates or considers "Why the eff are these places disappearing nvm we got ordered to the front we can't deal with this now" Regardless its your campaign so I'll presume its how you intended or how Aridon knew exactly where to attack and to cause the least amount of suspicion.
2nd playthrough Glitches: Fleshtearer Splitting spell doesn't have damage showing in the tooltip on Chapter 9 (Unknown if this is the same on previous chapters) "Veteran Walkyrie" Is this the actual name of it Valkyrie? unsure. Fist of Ice Level 2 and 3 Has too many spaces inbetween the Number and Meteor on the Level up screen text.
Might be one time but losing your DK hero didn't return the items at Chapter 9, I litterally have no idea what might of caused this but they re-appeared when I restarted the mission, might be worth noting though if others experience this.
Chapter 9: Demonlord didn't have the death animation, it just stood in a sort of T-pose, again with no idea how this happened as it came back when killing the next one. There seems to be some random "Suddenly day/night time" thing happening every so often, I'll see a flash of daylight and suddenly BOOM night time! Either that or its a really bright light that randomly illuminating the entire world. Progaderas reward is another +15 claw of attack, A bit underwhelming considering you get another one on the previous cave mission of chopping through about 500 trees to kill those Hostile demons.
Beyond the difficulty of the start of the map once you have gotten past that there is little difficulty in fighting the demons, I gradually just wore down their spawns by focusing the portals and then my ally literally steam rolled the "Final boss" he stood no chance as soon as the other heroes charged forwards. Maybe the attacks should be spaced out more with wait times such as 20 seconds between? So it starts with a few smaller ones and then has a much larger attack, The only real late concern is the Demonlords coupled with the heroes completely wrecks everything, but most of the time you won't encounter them all together. I recommend removing the Sleep spell from the Final Boss, him spamming it takes away a lot of his combat potential, like he just flails it around everywhere making him vulnerable as he attacks very little.
You can put a trigger to make brown an enemy but share vision, If its there I think we should be able to see the orcs/humans fighting against eachother otherwise Orange/blue/brown can be completely ignored, the first time I didn't even deal with orange when I found out he didn't attack me. I just went full force on red with production so I never really saw anything else. It wasn't untill I went back and thought "I wonder whats in the rest of this map" I doubt everyone is going to do that so I feel you should at least show off some more of the map so it isn't just 'wasted'
Apologies for the HUUUUUUUUUUGE wall of text.
Feedback delving the "Harder" difficulties I noticed it was things like "XP handicap" and adding Hardened Skin to every red unit? (On chapter 9 that is anyway)
I understand this might make it... Slightly more difficult but I hope you will find different ways to make harder difficulties a bit more of a AI improvement (Perhaps on hard Orange actually attacks you?)
I think that due to technical reasons its a lot more difficult to change the ai than it would seem, however I've seen various campaign do lots of things to make the game more difficult on hard as compared to normal, such as:
1) making the enemy attack more frequently
2) giving enemy hero extra items, for instance item with powerful aura abilities
3) adding more creep units
4) giving you less reinforcements
5) reducing starting resources (gold and lumber, as well as units)
6) reducing your research level
7) making certain units unbuildable
8) changing the composition of attack waves, making them harder to defeat
9) decreasing your hero's level
10) giving you a time limit
11) making the hero un-reviveable, giving u a game over if he/she is killed
12) making someone who was neutral on normal your enemy
13) giving extra hit points to enemy units
14) having you to take longer paths than in normal(destroying certain bridges)
15) lowering your food limit
16) giving the enemy heroes spell resistance
17) giving the enemy an additional base
18) upgrading the abilities of enemy units (for instance healing)
19) changing the armor of the enemies towers to fortified
20) making the enemy units have all chaos attacks
so there are lots of things which can make the mission much more challenging without having to mess with the ai which may be difficult in some instances...