Editing Warhammer 40,000/8th Edition Tactics/Genestealer Cults (section)

====Imperium====
*'''Space Marines''' - Can fire at units coming in from reserve with one unit of infantry, as long as the target is within 12", and they subtract 1 from their hit rolls, for a 2 CP stratagem. A unit of intercessors with a re-roll aura nearby can tear up T3 units, even with the -1 to hit. Generally SM depend on their comparatively expensive captains and named characters to boost their army and thus huddle around them. Kelermorphs, Jackal Alphus and well played melee assassinations slipping through the gaps in the SM chaff strip the SM of many of their bonuses making their shooty units less of a threat than basic Tau or an IG gunline. Ultramarines and Iron Hands have counters to your assault shenanigans thanks to the smurfs being able to fall back and shoot with a -1 penalty, and Iron Hands overwatch on 5+.
**With their new Codex, Marines are back and more dangerous than before with their Combat Doctrines. The Devastator, Tactical, and Assault Doctrines up the AP of all Heavy, Rapid Fire & Assault, and Melee weapons by 1, respectively. Some chapters also modify specific doctrines, such as Ultramarines who count as having stood still unless they advanced or fell back during the Tactical Doctrine. Correction, NOW a unit of Intercessors with a re-roll aura can tear up your T3 units by rending off your squads' 5+ save with AP-2 during the Tactical doctrine. Oh, Shock Assault lets all Marines get +1 attack if they charge, get charged, or heroically intervene so you HAVE to wipe those Primaris units you charge otherwise you'll get a nasty counter-assault.
**All Chapters including Deathwatch and Grey Knights got the Shock Assault rule in an errata, so the above point on SA applies to all of the snowflakes below (especially if they're close-combat oriented like BA and GK).
**Beware of their easy access to Scrambler arrays.  Depending on your meta, you may find certain opponents spamming them all across the map.  As you might imagine, this is a huge pain for any majority GSC army and likely a matchup you will struggle to gain any ground in.  
*'''Blood Angels''' - You should be able to easily keep him away from your deployment zone with smart blip deployment. Use Meticulous Uprising and ensure he can't charge anything of value turn 1. If you do go first, consider deploying Clamavus on the board to further screen out the incoming death company/sanguinary guard. Blood Angels armies are often coming to you, so keep positioning and safe deep striking zones in mind. On the other hand, if all of his stuff is coming at you, his backline should be very open and chargeable with a big blob of acolyte hybrids. If you can hold the initial deepstrike punch from him, then you should be able to decimate whatever he has left in his backlines. Beware of Baal Predators with flamers (unlikely though as why would anyone run a Baal Predator). 
*'''Dark Angels''' - Have the same Auspex Scan stratagem Vanilla marines have, while also principally focused on being a static gunline that is almost immune to morale, or fearless if they are {{W40kKeyword|Inner Circle}} units. Again, characters such as Azrael and Ezekiel are lynchpins for their insanely good auras. Deal with them first and watch their gunlines crumple. Ravenwing units can ignore cover with the help of their Talonmaster, a vehicle HQ that can still hide behind other units, making him a bit of a hassle to deal with since being a T5 {{W40kKeyword|vehicle}} screws with Sniper Rifles and Daggers that are mainly intended to be used against {{W40kKeyword|Infantry}} models. Belial and Sammael act like mini-Chapter Masters to their First and Second company units, respectively. Speaking of the Deathwing and Ravenwing; Terminators, Bikers, and vehicles are bullet hoses thanks to Bolter Discipline, making a mockery of your mostly T3 army at a 24" range. Don't let them kite you, get stuck in there quickly. Elite armies suffer greatly once the casualties start piling up, but remember your cheap hordes of Neophytes and Acolytes are strictly worse stat-for-stat and will die much easier than a space marine.
*'''Space Wolves''' - The Corgi "shoot at things coming in from reserves" strat requires the unit being targeted to be within line of sight of a Rune Priest AND it can be any unit that fires at the unit coming in. If they have a Rune Priest, kill him ASAP with a Sanctus using the relic sniper or keep your underground ambushing units out of the LoS of the Rune Priest. Their Chapter Tactic gives them +1 to hit if they charge, get charged, or perform a heroic intervention. It's...lackluster compared to the Blood Angels' similar Tactic, but it helps their unwieldy stuff hit its mark at least.
*'''Deathwatch''' - Their Mission Tactics let them re-roll 1s to wound against a unit type of their choice, and Special Issue Ammo stings like a bitch. The only way around it is if you have a detachment of C4AE units to stop them from swapping mission tactics mid-game once they deal with their chosen units. Frag Cannons and Infernus Heavy Bolters are a bitch. Luckily, so is charging from around a corner out of line of sight, the Mass Hypnosis power, and the Amulet of the Voidwrym relic to deny overwatch. They too can shoot at units coming out of reserve like normal Marines, but it has the same pitfalls as the Vanilla version. They also tend to rely on their comparatively expensive HQs, who would have guessed? Handle them as you would Space Marines.
*'''Grey Knights''' - These guys cry when they see a Magus in your list. Every squad has the potential to deny a smite against itself, within range of your Magus, obviously. Also, the Sanctus with the relic sniper has a field day with GK. Their Psychic Awakening book gave the grey bois some of that much needed love with their "tides of war" that can either let them re-roll 1s to wound in close combat for example. Ironically their best tide against us will be the one that lets them up the AP of all psybolt weapons by 1.
*'''Imperial Guard''' - With the Number of snipers available to the faction, you should be bringing 1-3 Jackal Alphus already. Their Rifles mean you should be picking off enemy Officers with ease, making the Guardsmen as average in shooting as you are. Just be aware that their characters cost next to nothing, and they probably got a Brigade Detachment, plus others in 2K. If you bought the Starn's disciples Kill Team set or kitbash a Commissar or Magus to make him, a Kelermorph is absolutely bonkers against a guard army. Remember: [[Meme|It's High Noon...]]  Also, Cadian gunline is tasty for ITC, as you can easily secure the entire board, whilst also ambushing in rapid fire range to remove their wall of guns in one turn. A safe bet for your cult creed would be the Bladed Cog, giving your entire army a 6+ invulnerable save (or +1 to existing invulns), making the guard's quality firepower a bit easier to tank.
*'''Adeptus Ministorum''' - The abundance of hand flamers can make your life hell when charging in. Once you do get in, you are going to tear their T3 models to shreds with the number of attacks that Acolyte Hybrids or Metamorphs can get. Beware counter charges from Arco-Flagellents as they will annihilate any unit they can get their hands on. In the same vein, their special characters can have some serious punch in melee, so beware of them. They traditionally have a lack of anti-psyker defenses beyond their 4+ deny stratagem. Bring a pair of Magus and a Patriarch and make their decision of what to try and deny really tough. 
*'''Adeptus Custodes''' - Mental onslaught states that you deal a mortal wound to the unit, but if the targeted models is still alive, the process continues. This is useful for targeting a unit that has a wound already, but selecting a different model, as it can guarantee 2 dead Custodes. See the Imperial Knight entry for how to assure the success of a Mental Onslaught. If you don't want to use psychic cheese, remember that while Custodes are insanely durable, you can always just swarm them in close combat and hope to drown them in bodies, and preferably Rending Claws too. 
*'''Adeptus Mechanicus''' - You have a Cult Creed that is designed to pinch one of the AdMech's quirks (Everything having an invuln) whilst also being very anti-Admech Fluff wise and even a little crunch wise. Chaos can only watch as the Bladed Cog's version of Death to the False Emperor procs on a 4+ against these guys (Sadly only as a stratagem, but you shouldn't forget it exists). Ultimately, you probably won't need it because the AdMech lack top tier melee units, but the idea of your acolyte Hybrids demolishing Infiltrators/Rustalkers is one you should remember should you bring Bladed Cog.
*'''Imperial Knights''' - Charge a block with 6 twisted Helix rocksaws into the Knight with a Primus giving their bonus either by strat to get closer or by +3 bubble warlord trait. The Rocksaws with a banner will be hitting on 2s rerolling, then not even using anything to boost the damage rolls are wounding on 3s rerolling, which averages 10 successful wound rolls (20 damage) going straight through Armor and then the minimum 20 claws and 10 daggers wounding on 5s rerolling can most likely finish it, add in ''Might from beyond'' and the saws can potentially kill the toughest knights by themselves.