I'd say at least train your warlocks until lvl 3 before thinking about research. Training remains more important, but having some of the spells won't hurt, especially sight to see which rooms there are to claim. And note that if you're playing with a nightly build or
KeeperFX 0.46U guardposts won't help with efficiency. Having the spiders/demon spawn researching sounds like a waste to me, if they can do that they can also fight to push onward and claim more rooms. And I wouldn't say it is trial and error, the level objective clearly states: "Heroes will attack. Raid their dungeon to gain power, or get crushed by the relentless heroes of this realm." This isn't a lie, you must attack or you'll be defeated. If you remember this, you should always win, but if you decide to turtle anyway, you'll die.
Basically this is the walkthrough for the level, so read on your own risk:
- Before you breach out, you can find a workshop to the north-west.
- You may train a bit before you breach out, but when you hear the heroes have found you you're late, quickly claim the library.
- Once you are healed up - time this right with when parties attack - claim your first barrack. When you're recovered from the counter attack also claim the second barracks so heroes don't have it available anymore.
- Quickly train up your Orcs a bit, when they have a few levels, I suggest to take the southern route first. If you're having trouble from the magical parties, go for their library first, if not, try to claim a prison.
- After you have either library or prison, find the second portal before taking the other room. At this point you should get a sizable army that can handle anything the map throws at you.
- Now decide: Push on to get the temple, or take the northern route to get the torture room. This depends on if you prefer skeletons or have some nice heroes to convert.
- Finish both routes now, get a large as possible army now with all the rooms you got, and prepare for the final assault by smartly placing traps: Spellcasting heroes will die easily to lighting traps. If you get dragons, they really help.
- Don't take too long, otherwise they will come out and destroy you. When you are ready, breach the final room with the hero hearth. Kill it and all heroes to win. Fight smartly, not every hero at once and use lightning to kill wizards and fairies.
General advice:
- Only have one entrance to your base to focus the fighting on, and you can use traps.
- If you don't have time to train all your creatures, be smart with the levels. Spiders are much more effective when they get freeze(use this spell well), demon spawn when they get heal, warlocks with heal/firebomb, trolls with speed, etc.
- If you slap a creature before a fight, it is 25% more efficient.
- Feed chickens to creatures if you quickly need them healed before a fight.