I don't want to be overly harsh since this is a beta campaign with only one map that's currently being worked so I'll try to keep it somewhat simple (Impossible Challenge, lez goooooo)
Criticism 1: Antherion is too OP or rather, his specter is too OP with the +10 stats and 2% HP regen. His specter alone trivializes most of the fights. I find myself auto-attacking more often than not because what's the point? His 2% hp regen keeps everyone so healthy that I didn't feel like using any of his or Aria's skills or even microing my units. I just attack move into the enemy and wait. Naturally, thanks to his specter, I finished the mission without a single death.
Criticism 2: I mentioned that I didn't feel like using any of the 2 hero's skills thanks to someone's specter but I have some issues with those as well. Antherion already has the specter so why does he have 2 healing skills? Holy Light and Chain Heal do come in handy from time to time, don't get me wrong, but I feel like him having 3 options for healing might be a bit overboard. Also, why does he have an extra skill in the form of Inner Fire? Why does Aria not have an extra skill? I feel like if Antherion gets an extra skill, Aria should as well. Moving onto Aria, I get it, she's a summoner but it'd be great if she had another skill. Maybe a support skill or a damage skill. This skill could even be her extra skill like Inner Fire was for Antherion. Also, this is a personal nitpick but I hate Aria's level 3 golem skill. Replacing the rock golem that has an on-demand stun with something like the war golem that is just a beat stick has been the worst trade deal in the history of trade deals, maybe ever.
Criticism 3: I said earlier that Antherion's specter is too OP but there were moments where it felt fair and balanced because the fights I was in felt unfair and unbalanced. The one that sticks out in my mind the most was the Troll Warlord fight. Why does he have resurrection? The entire map is unbalanced imo. The fights are either unfair to the point that having a healing stick felt fair and justified or so easy because said stick exists. It can get boring.
Criticism 4: Fairness, balance, and skills aside, let's talk about the rewards that are spread out across the map. Taking the Troll Warlord from before as an example. For such an unfair fight where he can bring back the dead, why is the reward from that fight only a voodoo doll and mana pot as well as access to a mana fountain? And you have to destroy a barrel and a building for the doll and pot respectively as well. There's a bandit lord as well and that fight only rewards a book of intel + 1 if you destroy his tent. There are more unsatisfying rewards out there that aren't worth the effort of actually getting them. The only good rewards, imo, are the Orb of Fire and the secret boss artifact.
Criticism 5: In fact let's talk about the Orb and the artifact. To get the Orb, you need to do an optional side quest. Fair but does that side quest really have to be in the way of the main quest? You can't continue the main quest without going through said side quest because the base where the side quest takes place is literally in your way. I have tried to disturb the base as little as possible while progressing through the main quest but attacking anything or anyone pulls everyone and their mothers inside the base towards you which means free Orb of fire. The completion of that quest felt forced. Also the secret boss. it's not a secret when it's literally right next to the road you have to take to do the main quest.
Criticism 6: So this is a beta campaign and it's still being worked on but there is no story. why is the village allied with the undead? The quest said "The region has succumbed to the undead" but how? Were the people possessed? Is this the work of cultists? Did they fight back but surrendered and are serving the undead in exchange for being spared? What's the lore? I must know. Why are the orcs here? Side quest orc said expedition but for what? The road is also very linear, it's just one road and you only go off it for the secret boss or most of the side quests. There is more i want to talk about regarding the quests like how you can't trigger the side quest where you kill all the creeps until you go off-road and fight one instead of fighting a small group in the middle of the road, which could prompt some dialogue before triggering the quest.
Criticism 7: Ok this one is also a nitpick, I'll admit. The orcs being named "Computer (Normal)" and the purple undead having no team identifier if you hover over them.... kinda triggered me. The orcs could be named "Orcish Expedition" and the purple undead could just be called "The Undead". Also, why are both the player and the orcs colored red? It made things confusing at times. Probably should change the team color there, either the Orcs or the player.
Criticisms aside, there are things that i do like. First and foremost, despite all of my criticisms, this is still rather fun. it's a good time sink and some of the stuff within is quite funny (Timmy, what have they done to you? I remember when you were just a little village boy who was rescued by Arthas). There was a good bit of customization like the Elite grunts and captain (really should it to elite footman imo). I feel like this could go on to be a really good campaign given the premise of the story in the loading screen. Also please change Aria's rock golem skill, the War Golem at level really irks me. if you want my suggestion on how you can improve it, maybe make the level 2 golem a slightly buffed Battle Golem and level 3 a slightly buffed Rock Golem. i dunno, losing ther rock throw hit alot harder than i thought it did.
Edit: Also having using iseedeadpeople, i have one question. What that murloc doing? Bro is looking out into the sunset from his waterfall, contemplating life or something.