Difficulty levels

Multiplayer AI has 5 difficulty levels, Most Gentle, Gentle, Normal, Hard and Brütal. Harder AIs tend to be more active and more concentrated on the game, but do not have cheaper units nor more income. While Most Gentle AI will frequently forget to recruit units, command them rarely and use the avatar rarely, Brütal AI will start recruiting even during the mission start screen when players can't, will target units immediately at fan leeches, focus units on many targets simultaneously and use their avatar in any confrontation, using solos whenever possible, attacking and dobule-teaming constantly. Defeating the Most Gentle AI is easy and even the greatest mistakes are unlikely to allow them to win. Defeating the Brütal AI requires a superior strategy because it's extremely hard for a human player to concentrate on so many targets.

Defeating the Brütal AI

Brütal AI can be relatively easy to defeat on some maps, such as Feeding Area, Altar of Blood, Crucible of the Titans or Death's Fjord. In Feeding Area and Crucible of the Titans, AI will easily get its units killed by environment and the player doesn't have to face so many of them. Similarly in Altar of Blood, the Blood Trap can kill all enemies in the pool and help you greatly (getting the environment to kill some enemies might need some help from the player also in Crucible of the Titans). In Death's Fjord, AI will focus both on the valley and on the stream and if you send all of your units into the valley, you can take control of this area and get a huge advantage. But many other maps aren't so easy.

A strategy that almost always works (the battles are most likely to happen as described, but some improvisation in later parts will be needed):

• phase 1 - If you are playing with Drowning Doom or have only one starting merch booth, fly towards the nearest fan leech and place there a beacon, otherwise fly towards the enemy megastage. Then, when the mission intro screen disappears, it's time to recruit. If you have two starting merch booths and you're not playing with Drowning Doom, recruit nothing (Drowning Doom's Ratgut needs to be supported by some Grave Diggers). Otherwise recruit a squad of melee units. Start attacking the newly recruited enemy units with your avatar and try to kill a couple of them (if the enemy is Tainted Coil, it's possible to kill their first Battle Nun before she spawns anything, but Doviculus will keep hitting you all the time and you'll be low on health). Send your units towards the selected fan leech and return to battle (skip this if you have Ironheade or Tainted Coil and two starting merch booths). Keep attacking the enemy units and flee to attack a new batch or help your units attacking the fan leech if they wound you too much, but don't send your units against them if it can be avoided. Upgrade your megastage as soon as possible. Continue preying on enemy units, you can expect to have over 10 kills at this point During this avatar guerilla, you'll see the enemy avatar protecting his units, if it happens, attack a different squad elsewhere, he or she will annoy you to no end, use crippling solos and use annoying double teams (killing him/her brings little advantage). Beware of larger groups of ranged units, and kill ranged units first (your mobility will let you avoid most melee units' attacks, but not ranged units' attacks). If they attack your units, fight with them. If your units scare a fan leech away, build the merch booth. Proceed to phase 2 when the keep is upgraded.
• phase 2 - When the upgrading ends and it's possible, recruit your faction's infantry killers (Fire Barons, Ratgut or Tick Choppers and Pain Lifter), and continue annoying the enemy with your avatar. The enemy will probably be already fighting your first spawn if you have recruited them. Send your infantry killers to help them. At this point, the enemy will have more merch booths and therefore more income, but you have stronger units. A larger battle will occur probably at this point, and losing it can be fatal. Use your avatar to protect your higher units (Drowning Doom will always need Grave Diggers for this), especially melee units that happen to start bashing into them uncontrollably (this should not happen much) and ranged units (especially problematic with Razor Girls). Recruit and send more units into this battle, if you have enough infantry killers at that time and you're playing with Drowning Doom or Tainted coil, send a support vehicle there or a couple of them, they're cheap. If the enemy faction isn't Tainted Coil, expect the enemy to loosen the grip for a while and surprise you with tier 2 units, if you suspect it then recruit and send one or two general purpose ranged vehicle there. The enemy will most likely surprise you with infantry killers that are hard to counter with avatar, so use guitar attacks on them. If the enemy is Tainted Coil, Doviculus will keep spawning units and may never upgrade his keep, making the rest of battle easier. If you see that you're winning, upgrade your megastage and proceed to phase 3.
• phase 3 - When your megastage is at stage 3, recruit a tier 3 infantry killer and a tier 3 vehicle killer (might be useful to get more of them, especially with Drowning Doom's Broods). You have most likely defended one or two merch booths, but the enemy controls the rest and is preparing for a payback. Attack an enemy merch booth of your choice and prepare to face the enemy army. Also, don't forget to bring the newly recruited tier 3 units. Get a Dirgible if your faction is Drowning Doom, it has a load of hitpoints and supports nicely. Don't separate your units, keep the army together, if smaller squads attack one of your merch booths, try to kill them with your avatar and/or send a unit there. Don't delay the confrontation too much, the enemy may create too many units that will be massed and will do a lot of damage. Your avatar will not help much, but try to use some solos, double team or protect your vehicles from melee attackers. Recruit some more vehicle killers during this fight and bring them to battle. Ironheade AI is quite likely to surprise you with a brand new Rock Crusher by the end of this confrontation, so be prepared. If are facing Tainted Coil, don't kill all of their hierarchy units, they may summon a Bleeding Death and destroy your winning army like nothing. If you lose this battle, it probably isn't fatal, but it will be harder, just keep recruiting in peace until the enemy starts attacking your merch booths.
• phase 4 - Don't split up and start conquering enemy merch booths one by one. The enemy will be attacking you or your merch booths frequently, chase them and fight them, but don't split up unless it's really necessary (sacrificing a merch booth can be better than risking high casualties). Keep replacing dead units, try to keep your army's units balanced against all kinds of enemies and have enough support. When you control most merch booths, send all of your units against the enemy megastage and enjoy the siege.

Things not to do:

• Don't debase yourself with wakening the enemy avatar with solos like Chains of Hell or Anvil of Burden, the avatar isn't worth the time and you'll take a lot of damage while doing it.
• Don't freak out and arrive with all your units when your megastage or a merch booth is attacked. Many attacking units can be defeated with your avatar easily if they aren't focusing on your avatar, and the building has enough hitpoints (and many enemies will prefer attacking the merch booths near the megastage than the megastage itself). If it's the megastage that is attacked, it is worth recruiting a unit to counter them, though.
• Don't linger in the air for longer periods of time, better go attacking something.
• Don't neglect support units, especially with Drowning Doom.
• Don't neglect solos, Ironheade's Battle Cry, Tainted Coil's Martyrdom before battles will have more effect than striking some units with your avatar and Facemelter and similar solos kill enemies much more effectively than normal combat.

Some tips:

• Preemptive strike can be very useful at times. All enemy units will return to the keep and give your other units time to attack less valuable targets. Also, you can get lucky that the enemy won't be able to defend himself.
• If you're playing with Drowning Doom, playing Black Tear Infusion is useful at any time when some units have just defeated some enemies.
• When attacking a tier 1 enemy unit with the avatar, it is useful to start the attack by setting it on fire. The fire will have enough time to deal significant damage through the combat. If there is a group of enemies massed together, using a charge is useful, guitar attacks need little aiming and this one will also damage many of them.
• By controlling the population of Tainted Coil's hierarchy units, the enemy tech level can be controlled, so better don't focus on them unless you don't really need them to stop breeding.
• When attacking a building, it is almost always a good idea to send them towards a beacon placed just next to it and not at it, the units will attack any nearby enemies and attack the building only if there are no enemies. Otherwise they would take heavy damage and possibly fail destroying it (and if it's a merch booth, the enemies have to be killed before having any use of it anyway).
• If you're on a smaller map and playing with Ironheade, a zerg rush can let you win in a couple of minutes. Recruit a lot of Headbangers and send them against the enemy megastage (ideally using a beacon placed there). Keep recruiting more of them and sending them towards it. Protect them from defenders yourself. Might be used also with Tainted Coil, they can spawn reinforcements right near the keep, but their melee infantry is weaker (double team with Soul Kissers might help destroying it).
• Sometimes, sacrificing your avatar is worth it, especially when waiting for some important reinforcements to come, taking heavy damages every second while they are away.
• When playing with Tainted Coil, unleashing a Bleeding Death near the enemy megastage will most likely result in heavy casualties inflicted and damage to the megastage, saving time to do anything with other units.
• When playing with Drowning Doom, using an organist's double team to possess an enemy Rock Crusher or other strong unit can make a significant change. Frightwigs can possess too, but they aren't very useful otherwise.
• When trying to damage enemy Drowning Doom units with avatar, focusing on Frightwigs is useful. They don't deal damage when attacked and don't have as much hitpoints as a full squad with the same cost.