I've been playing through the single scenarios in HOMM4. It seems as though Castles are almost completely impregnable. A relative small and weak army can repel a much larger and stronger force from within a Castle. That's OK, I suppose, but it can make capturing enemy castles in the endgame very tedious.

Any tips?

Oh, and I'm using the Equilibris mod, so possibly that's part of the problem?

HOMM4 has some serious balance issues which is one reason why the game got a lot of criticism. Shooter units on the towers can really only be hit effectively with magic, ranged units suffer a damage penalty and of course, melee units can't get to them. THis is where order magic really shines (also imbalanced BTW). A forgetfulness spell can completely incapacitate a shooter stack. Failing that, you always have damage spells and certain units can cast damage spells too.

Another option is using summons to break down the front gate and hope the shooters target that unit but it doesn't always work.

Even the lower level spell displacement can flick an ememy off the tower causing him to lose a shot that turn.

If your problem is with melee units, then use summons to break down the gate and attack those stacks with magic and missle attacks.

High level heroes also make great damage sponges. Make sure they're under the effects of the revive potion (every faction has them) and move them forward. High level heroes are ridiculously overpowered in HOMM4. In the barbarian campaign, Waerjack can solo the campaign after the first map.

Great tips! Thank you very much!

Glad to have been of help. Theres other ways but to deal with base defenders too but you'll probably find them out. Enjoy the game :)

Strange... I never experienced some troubles besieging the castles in HoMM IV. I would say you could have some difficulties when your hero's skills and abilities are not suitable for sieging.

A stack on a tower gains - I think - both an attack and defence bonus - regardless of whether it is a defending stack or an attacking one. If you are able to get a strong stack of your own on one of those towers - Teleport spell is useful here! - said stack could just wreak havoc inside the walls. This works really well if you can teleport a fast and strong shooter onto one of those towers. Melee units are good too, but can only attack adjacent targets.

It becomes a slaughter fest if you get a stack of your Vampires on one of those towers if your the attacker.

I cannot recall if the Castle Tower Defense bonus is a % or a flat bonus. I think it's % based though which makes it so much better to get T3 or T4 guys on there and not so good for lower guys. Also think it gives a bonus to attack as well.

"Melee units can't get to them"? What? Of course they can.

Actually yes, that's exactly what it does - it deals with the stack on the towers.

*sigh*, I seriously hope your just missing the point and not trolling me here.

There is nothing difficult or confusing about this. The idea is to disable shooter stacks outright or reduce their numbers thus reducing their damage on the FIRST turn BEFORE they get their FIRST shot and not have them get three or four turns worth of shots at melee units trying to bash through the front gate. Melee units CANNOT bust through the gate and engage shooter stacks on the FIRST turn (Devils excluded). Did I mention this was for the FIRST turn? FIRST turn is the key point here. Not second, not third, not ninety ninth, FIRST!!!! Unopposed shooter stacks can turn your army into dog meat pretty quick, against a decent sized army, you just can't wait for melee units to close the distance.

Yes, I'm aware melee units can go through the front gate and engage shooter stacks on the towers but that approach wastes melee units. You still have shooters/casters on the towers and melee defenders get a damage bonus against your units when attacking through a wall. This mean you'll have less units than you could have and will make future castle sieges and continued pushing into enemy territory more difficult than it needs to be. You should be cutting your losses wherever you can not just blindly charging in.

I find your difficulties with castles a little strange personally. One of my criticisms of forts in HOMM4 is that it is overly simplistic and does not provide the defenders a real advantage. (I say this from the perspective of one that grew up with HOMM4 and actually like it more than other games in the series.)

The thing about castles is that they make the AI do retarded things. If your army is stronger, then the enemy will cower behind the walls and never attack, allowing your spellcaster to release plague and poison galore, or else summon a huge amount of monsters so that your real units don't have to fight.

Other than that, if the enemy has shooters, it tends to become a shooting war until such a point that you breach the gate and have a little brawl there.

Yeah, I posted this when I was still very new to the game.

First of all, you're right that forts and citadels do not offer much protection to the defenders. But I was speaking of castles (the final upgrade with the turrets). As other posters pointed out, there are some very effective strategies for overcoming castles. Order Magic is big for overcoming them, and certain troops (like Mages) can make it far easier.

That said, if you're in a situation where all you have is Might troops, and the defenders have lots of shooters in the turrets, a castle can be very deadly to siege. There's a lack of overall balance in that not every faction is well-suited for sieging towns.