I just finished the 2nd level of the Beyond the dark portal human campaign...you've got three enemy orc bases...but only one was really bulding units and attacking me.
It was the same in the final missions of the WC2 original campaigns.
Is that normal behaviour? Or is there a chance the AI might be broken somewhat in this release.

The thing that irritates me about that 2nd human level in Beyond the dark portal is that it explicitly mentions dragons in the briefing...but I didn't get attacked by even a single dragon.
I also had a short look at a walkthrough video and someone mentioned in the comments that in his version he was attacked by dragons, ogres and death knights (whereas in my playthrough it was only grunts, axemen and a very few orges). So this sounds like there might be drastic differences in difficulty between different versions of the game.
Bit sad if the Gog version is flawed.

The AI has a general script. They focus on land, sea, or air. In spite of this, there is a random element to it. I've been playing BtDP and I've been reloading a lot. I would prepare for an attack in one area, based on what happened before I reloaded. But sometimes I am attacked in a different spot or with different units. The fact that you didn't have to face dragons is probably luck of the draw.

The thing is, the orc base with a dragon roost didn't build any combat units at all. They had peons collecting immense sums of gold, but didn't do anything with it. Which seems pretty strange.

Sometimes it could happen, try next time Save and reload mission

The campaign AI in Tides of Darkness and Beyond the Dark Portal (and Starcraft for that matter) was based on a "trigger" system. To keep the missions from being too overwhelming, certain enemy bases would remain on standby, just sitting around mining, until a certain condition was met which would activate them. Normally this condition would be moving your units past a certain point. A great example of this can be seen on the last Human mission in Tides of Darkness: Black only "activates" when you move out into the northeastern portion of Orange's former base. If you never go there, Black will just sit there mining all mission and not do anything (a great way to cheese the mission, by the way).

So it's possible that you just never activated the trigger. Unfortunately, I don't know of any way of being able to dig into the maps themselves to find out what the triggers are - AFAIK most of what we know is based on trial and error. It's also possible that the trigger was somehow broken. Sometimes restarting the mission will fix things.

It's possible that it got broken in whatever tinkering GOG did to release it, but I know that even in the original version there are issues like this. I think it's mostly just a weird byproduct of the way Blizzard programmed their AI back then. It tends to be more obvious in BtDP just because most maps there involve you squaring off against 3-5 different factions.

Thanks, that's very informative!
I had already suspected something like this, because I had played the last human mission in Tides of darkness many years ago, and I seem to remember that if you moved ground units eastwards to the black base, it would trigger pretty annoying attacks by death knights coming with their area of effect spells for your base...which didn't happen otherwise.
Still a bit disappointing, but the issue seems to lie mostly with the original programming.

I've noticed the AI just gets "stuck" like sometimes and it kind of bothers me. It happens a lot in the original campaigns. I remember some missions you could get attacked relentlessly, but other times, the AI would do absolutely nothing at all. I'm not sure about the trigger system honestly, because a lot of times when the AI was aggressive I didn't even move out of my starting areas and other times, when being all over the map, it wouldn't do anything (like others said, just mining gold, not building ANY units, researching upgrades, or even repairing).

Save and reload would sometimes help and the AI would suddenly "activate".

I played the last mission in the ToD human campaign yesterday and black didn't make a single peon (full gold mine for me, I guess). And the mission before that often used to be scary as both AIs would send transport ships full of ogre mages that would attack you, except not this time. They did one pathetic attack at the beginning of the mission, then stopped entirely. I even played with the AI to see if there was something I could do to make it active. Somehow I made it do some upgrades eventually (most of the map was conquered already), but then it would stop again. I just don't know.

The only trigger I know of (universal) is when you destroy second to last, or last building of the AI, it will send all units to try and attack you (even peasants lol).

You are wrong in this mission black ai has got to make 0 units, they just upgarde everything (ships,ogres,trolls,dks)
Dks didnt attack you till you go to northrest of orange base cause they stuck somewhere

This is black ai

upgrd up_paladins ; upgrade Knights to Paladins
learn sp_paladin_A ; Paladin spell A
learn sp_paladin_B ; Paladin spell B
learn sp_mage_A ; Mage spell A
learn sp_mage_B ; Mage spell B
learn sp_mage_C ; Mage spell C
learn sp_mage_D ; Mage spell D
learn sp_mage_E ; Mage spell E
upgrd up_footmen_B1 ; Footman,Knight upgrade B (1/2)
upgrd up_footmen_B2 ; Footman,Knight upgrade B (2/2)
upgrd up_footmen_A1 ; Footman,Knight upgrade A (1/2)
upgrd up_footmen_A2 ; Footman,Knight upgrade A (2/2)
upgrd up_rangers ; upgrade Archers to Rangers
upgrd up_rangers_A ; Ranger upgrade A
upgrd up_rangers_B ; Ranger upgrade B
upgrd up_rangers_C ; Ranger upgrade C
upgrd up_shipcannons_1 ; Ship cannons upgrade (1/2)
upgrd up_shiparmor_1 ; Ship armor upgrade (1/2)
upgrd up_shipcannons_2 ; Ship cannons upgrade (2/2)
upgrd up_shiparmor_2 ; Ship armor upgrade (2/2)
reset_land ; reset land attack trigger
reset_water ; reset naval attack trigger
reset_air ; reset air attack trigger
strat_on ; ? strategy on ?
aggr_high ; ? high aggressiveness ?
size_land = 0 ; set size of land attack party
ptys_land = 1 ; set number of land attack parties
size_water = 0 ; set size of naval attack party
ptys_water = 1 ; set number of naval attack parties
size_air = 0 ; set size of air attack party
ptys_air = 1 ; set number of air attack parties
footmen = 0 ; set # Footmen
archers = 0 ; set # Archers
knights = 0 ; set # Knights
ballistas = 0 ; set # Ballistas
destroyers = 0 ; set # Destroyers
battleships = 0 ; set # Battleships
transports = 0 ; set # Transports
submarines = 0 ; set # Submarines
mages = 0 ; set # Mages
demosquads = 0 ; set # Dwarven Demo Squads ? (Computer won't train them)
flyers = 0 ; set # Flying Machines
gryphons = 0 ; set # Gryphon Riders
peasants = 0 ; set # Peasants
tankers = 1 ; set # Tankers
Loop:
sleep 30000
goto Loop

ai is doing only one tanker (ai got 2 yards so it will be 2)

I have reedit w2 campaign

look at my mission tod human 4
https://www.youtube.com/watch?v=0Ei5heBCFqI&t=2s

Cool video, those are some nice mass battles!

Well, in my last run, black upgraded up to berserkers level 4 (and ogre mages and dks), but his ships stayed at lvl 1 (it had PLENTY of time before I attacked him while having foundry up).

Where did you find this information? Very interesting :-)

Wardraft +mpq editor
Ai sometimes stuck no idea why, if you see that next time just save and reload game

Yes, that's what this thread is about, I'm pretty sure :D