Nexus Wars has consistently held a top spot in SC2 tug-of-war games, and it doesn't seem to have an up-to-date strategy guide. I figured I might as well try to write one.
So, a little bit about me. I am a diamond 1v1 protoss player and play one ranked match per season to confirm this fact. I play many of the top custom games and usually have a high win:loss ratio, and I'd like to impart some of my experience to help newbies out.
How the game works:
You spend most of the game building structures, which automatically produce units, which automatically go and attack the opponents base. The gist of Nexus Wars is to build the proper structures in the right order to overwhelm your opponents' base. Each team member is granted resources every 15 seconds; income starts at 10minerals / 15s and increases by about about 2minerals / 15 seconds for every 50 minerals you spend. Each team has as supply limit of 360, divided evenly among each member (so each member usually has a 90 supply max).
The map is laid out like so: There are two long, horizontal lanes connecting each base. The game is 4v4, so naturally each side of the map is shared by four allied players. It's common for 2 people to take one lane and stick with it for an entire game. However, there are benefits to building structures in both lanes as certain races have certain strengths. It's can also be beneficial to build structures in the four middle hexes, as units produced there may be rallied either north or south, which increases that teams survivability and flexibility.
marine (barracks) - a fragile unit with decent DPS vs non-armored, and poor DPS vs armored. Marines can be useful, but are very much a niche unit. They are generally ineffective without a unit to tank damage for them because of their low HP and relatively short range. Achons are ideal for this purpose as they aggro air units, but ultralisks and even firebats will work. With upgrades marine damage scales very quickly, so early upgrades can catch opponents off guard. They are weak to AOE, like banelings and storms, but with a tanking unit AOE is ineffective. Best countered by a few sentries for guardian shield and units with high armor. E.g., ultralisk-marine likely beats archon-marine, while the latter may be better overall.
reaper - detectors. overall, very volatile. Many people will choose between zealot, sentry, and ling in the beginning, all of which reapers kill easily, so getting several reapers is an easy way to push into an opponents base if they aren't prepared. However, reapers fare poorly vs roaches and very poorly vs stalkers, so if you get too many right off the bat you may fight yourself in some trouble. As they are low HP, SCV attacks can repel early reaper attacks from opponents. Firebats, with their 2 armour, are a good counter to mass reaper.
marauder - A very good anti-armor ground unit, in my opinion. Great early game against roaches, stalkers tanks and even thor. However, I would say they are not ideal in ANY end-game composition. Despite this, I use them frequently. Stim pack greatly improves DPS, reducing their attack rate from 1.5 to 1, and with medivacs, they can lead to scary early game pushes. Best countered by non armored things like archons and better anti-armored units like tanks
firebat - very powerful against all light unit compositions, but they lose effectiveness over the course of the game very quickly. They do counter reapers, marines, sentries, zealots lings and banelings pretty well, so it may be worth if to get a few.
ghost - quite expensive, but they give a lot of money for their supply (+6 for only 2 supply). Their high range, and lack of projectile (they fire instantly, no loss of DPS, and first strike) make them among the premiere units lategame--especially after 40 minutes. Stalkers counter them well, along with other armored units, but against zerg and light units, they are among the best counters. Make sure to place them far back, I think they get more energy for sniping that way.
hellion - these guys actually micro themselves, which is quite nice. However, hellions are rarely used for anything but unlocking tech. They do counter light units, so if you run into mass lings, queens or marines or something, the would be good, but that rarely happens. I find the have great synergy with stalkers, and using this combo you can sometimes catch an opponent off-guard.
tank - great range and DPS, but sort of slow spawn rate. Some people swear by them, but I rarely seem them used to great effect. They spawn too slow to counter marauder, and they are simply too fragile to be compared with thors late game. Named howtoadd.
thor - overall, a pretty awesome unit. High health is great for counter pushing, and gives them some resilience to Kerrigan. They are very good vs light air and vs ground. If opponent is not going armored air, thor + ghost is very hard to beat. You can rarely go wrong with thor. The downside to them is that they are very slow, so you shouldn't really be able so surprise your opponent. As opposed to something like hellion stalker, which can push a lane a few minutes, thors may take 10 minutes to push, which is bad for lag. I recommend not getting too many, it's silly to see a massive clump of thors, of which only the first row is firing. Mass thor can (and has) been countered by mass banelings, but immortals are the best counter overall, along with VRs, IMO. Ultras also tend to tank even thors very well.
dingle - this is a science vessel. Useful in almost any situation, just don't get too many. Esp. useful for supporting protoss, as almost all their units are armored. Dingles are the best overall detector.
medivac - quite good for healing bio, meaning they support zerg the best. Makes your army significantly more resilient, and you can rarely go wrong with getting 1 or 2 for each lane. Again, make sure not to get too many.
viking - the best anti-air anti-armor DPS, and their DPS scales well with upgrades. However, they are fragile, so make sure to support them with AA tanks, like corrupters and battle cruisers. vikings can be almost totally nullified late game by a well-played kerrigan because of their low HP, but otherwise are aces of the air.
banshee - has very good DPS and cloaking comes pre-loaded. If your opponent does not counter appropriately, you can likely push to their base. Banshees counter immortals very will. To counter banshees, use sentries, thors, ghost, vikings, pheonix, etc.
battle cruiser - primarily and anti-ground unit, that can also soak up a lot of damage. Their high survivability makes them useful for pushing cannons. Their short range fails them later in the game though, especially after the 40 minute mark, when they simply don't spawn fast enough. So, overall pretty situational, it's useful to get a few, if only to tank.
lings - 35 HP is too little to make them useful for much. Get 1 to unlock tech, that's all. I have used to in combo with ultras and banelings to simply overrun the opponent, but that's only because i had a significant lead.
banelings or madbao - Situational. They are rendered useless vs tanks like zealots, FBs, ultras, archons. They spawn surprisingly slowly, 2 every42 seconds. They do give you +3 income for 1 supply, which is very nice, and can be used to overrun opponents if timed correctly, but otherwise are pretty weak.
roach - quite good early game, quite bad late. They are cheap, 75 for 2 supply, and quite powerful for their price, but you will find they are simply inferior to longer ranged units as the game goes on. reaper + roach is a pretty common and devastating opening. If your opponents of gone for their banpeis, and you/your teammate make reaper/roach, you will likely cause significant trouble.
hydra - the marine of zerg units, and by that I pretty much mean they are exactly analogous to marines. Due to their higher HP, the can be used to some degree of effectiveness to counter anti-armoured units like immortals, but they are best used with a tanking melee unit.
queen - note, unlike ladder, queens are tagged as light. Queens are mainly for detection and a great counter to banshees (though i didn't mention them earlier). They are significantly better at anti-air than they are against ground. Almost always a good idea to get a few, as transfuse is good for supporting your other biological units.
infestor - I am not sure I have figured this unit out. It has very good range (7) and very bad DPS (8?). Good income to supply ratio (+6:2). Mass infestor isn't hard to counter IMO, use armored units, like immortals, Kollos, thor, etc. Infestors use energy, so i think it's beneficial to place them far back. They can do some scary pushes, because they tend not to die due to their high range. They seem to benefit a lot from medivacs for this reason. They spawn slowly though, 50 seconds for 1.
lurker - detection is require to beat these guys, but they are quite good at countering detectors. They do bonus to light (15 regular 20 to light), and do line damage, so they counter reapers, sentries and queens very well, along with other light units. They have good range and don't really take up any space. Don't be afraid to use a scan to keep their numbers down. Overall, lurkers can be pretty scary, especially vs all light units, but I think i remember them having a bad income to supply ratio, so maybe avoid getting too many.
ultra - the best anti ground tank. They spawn slowly, and are most useful to support your units that have low HP and high DPS. They actually move too quickly for might liking, sometimes they get ahead of your forces and die. They are great for pushing cannons. If you are defending vs them, make sure to target fire the weaker units with the cannon. Ultras lose to ground anti armour, like immortals, but can be used to simply overrun ground forces if your opponents are not careful. It's possible to win games by focusing on ground, while your opponents BCs tickle the ultras from the air.
mutalisk - pretty weak overall, but they are the fastest air unit that you can unlock (50 for ling, 100 for hydra, 100 for muta). Rushing to air works in some situation, and can stop all ground pushes of roach + reaper. Don't get too many muta, as they aren't very good.
corrupter - their DPS is subpar, but they make up for it with their stellar HP and corruption ability. Best used in combination with other AA, like Vikings and VRs.
brood lord - they only take 4 supply and cost 250, so their income to supply ratio is quite good. But they are only good in certain circumstance. They counter armoured ground pretty well, like thors, immortals, tanks, but they spawn / damage too slowly to be effective in all circumstances.
Zealot – 1 on 1, it beats most other units for its cost; however, since it’s melee, it quickly loses effectiveness as the game progresses. Most of the time, it’s best to get 1. Because they have some bulk, they can be used to push cannons, but they are not the best unit for the job.
Sentry – getting 1 sentry is good in almost 100% of circumstances, just don’t get it too early, as sentries have bad DPS and are valuable pretty much only for their guardian shield. Mass sentries is not a viable strategy vs. experienced opponents, so please don’t go mass sentry; mass guardian shield makes the game lag
Dark Templars – generally, don’t get these. Occasionally, they can be useful if your opponent neglects detection for a significant amount of time. However, due to being melee and slow spawning, they do not do well in the majority of situations
High Templar – one of the best units for softening counter pushes. They have very bad DPS (they actually have a non storm attack, that is), so don’t get them too early, or you will likely be overrun. Their storm damage is tripled after the 40 minute mark, making them one of the best units to have at that time. Make sure they are not synchronized. If you have 3 high Templars, it would probably be best to have one spawn every 16-17 seconds (they take 50 seconds to train each). They always storm the nearest thing, and only storm so often, so melee units can counter HTs by baiting storms.
Stalker – quite a unique unit, sort of a jack of all trades. It has passable DPS and can attack air and ground. Its best trait is its survivability, as it has good health and blink. I prefer to use them to support other tanky units. They run in front, take a hit, blink back, and allow your push to gain traction very quickly.
Immortal – one of the best units on the ground. Has very high anti-armor DPs and great survivability. They are almost always worth their cost, the challenge is getting the right amount. If you win the ground war and lose the air, your immortals will look pretty silly. If your opponent only has ground, then you should almost definitely have immortals.
Archon – the best overall tank, IMO. Unlike other tanks, they agro air units. They also have immolation I think, and their DPS is pretty decent, especially vs biological.
Colossus – awesome anti-ground unit, but quite susceptible to air, and slow spawning. Their range and damage output will help significantly in all ground wars, but winning the air battle is often just as important if not more important so make sure not to overcommit to the kollos.
Phoenix – mostly useful for unlocking VRs and carriers. They are great against banshees and actually pretty good even vs armored air for their supply. They are too fast however, and will often just die by speeding ahead of your army, which is why they are overall inferior to Viking/corrupter.
Scout – have a poor income to supply ratio and poor DPS vs ground. They are, however, decent anti-air units. They are mainly overshadowed by the fact that vikings, which are roughly equivalent in AAA(antiarmourair) DPS, and corrupters only take 2 supply, whilst scouts take 3, so you can't get as many.
VR – awesome income to supply ratio (+10:3), and very good vs armored and massive units. The only problem with them is that they are take a while to have a significant presence, as it costs 250 to get 1. If it weren’t for Kerrigan, they would be THE premiere air unit, but since they are fragile relative to carriers and battlecruisers, they have some competition. If you get them too early, you may be overrun. You cannot really rush straight for them.
Carrier – awesome range, great damage, especially with upgrades, and great HP. Carriers are the beasts of the sky. They spawn very slowly, and move slowly, but a massive push of carriers is almost impossible to stop without a nuke or Kerrigan. They are the best AA air unit past the 40 minute mark.
Building placement and syncing units:
Building placement is one thing that separates experienced players from the newbies. Early game, building in vertical columns so that units spawn in a vertical line is quite beneficial, and can mean the difference between pushing and not pushing a lane. It’s generally best to reserve the last few columns for air units, as to not interfere with ground units. Spell casters also gain some benefit to being in the back, as they will have more time to generate energy.
Syncing units is even more important than where you put the buildings. Note that syncing units means syncing you and your teammates opponents whenever possible, not just your own. Most units perform better when synced. The notable exceptions are high templars and tanking units. All it requires to sync units is to cancel production. By highlighting all buildings of 1 type and holding [esc] until all production has stopped, you can sync units (they will automatically start to rebuild).
NUKE – you are given one nuke for the game. It destroys everything in a large radius, and is best used strategically. Nuking instead of cannoning can give you the edge you need to win the game. If you win a game without having used any nukes, kudos to you, but all that means is that you probably could have ended the game faster had you used your nuke strategically. I generally use mine while teching to my 900 banpei before getting Kerrigan. Also, it’s often worth it to nuke if your cannon is going to die.
Cannons- 2 can be built, 150 minerals each, and each can be upgraded to a chelupa cannon for 300 minerals. They are invaluable for turning the tide of the lane. You should be able to tell if an opponent is pushing and gaining momentum (his mass of units will be getting bigger as he pushes toward you). It is possible to push while losing momentum, in which case you will likely not need to cannon. Make sure you are proactive about letting people know that you will need help repairing the cannon. If cannon will be taking heavy damage, make sure you chronoboost it, it will dish out more damage and be repaired faster. Target fire those enemies that have low HP and high DPS
g- teleport- get places fast by teleporting with G click. It cancels your move command, so you have to g click and move, but it’s worth it to get a cannon 1 second faster, or build a building 1 second faster, sometimes.
Nexus abilities, scan and chronoboost
As you approach the midgame, it's sometimes valuable to scan your opponent’s base, especially to check exactly how many air units they have, so you can just build enough AA.
Chronoboost is generally only used on cannons, but if you max out on upgrades, you should chronoboost your buildings to make units faster. You can also chronoboost a thor or something to help with defense of your base.
Tip ; watching your opponents income, especially early game when they have fewer options, is an easy way to tell what is coming. It let’s you know when they are getting their banpeis, and when it might be safe to get a pylon of your own.
The banpei (pylon) – a building that costs no supply and can be upgraded to give you an income advantage. Does not give you any units / immediate offensive presence. Effectively it presents a risk reward situation. Costs 175 minerals, Can be upgraded 4 times, costing 250, 450, 900, 1800.
Knowing when to get the pylon is certainly crucial to victory. If you are pushing into your opponents cannon, then it is an obvious you should get a banpei. There is no magic time at which you should get your pylon, but it’s generally okay to get it if you are pushing. It’s also pretty safe to get your pylon if your opponent has light/low HP units. 4 SCVs attacking can easily kill a bunch of reapers, marines and lings. Be more wary if your opponent has stalkers or roaches , as those will probably require a cannon, which would negate any benefits of getting an earlier pylon. Also note that I believe it’s best to stop at the 900 banpei or before it in the majority of games. After getting the 900 banpei is when you should get a hero and upgrades. If things seem like they will go on into the late game, then I recommend going for Kerrigan and then the 1800 banpei. Pylons can be killed by zeratul; with this in mind, I find it best to keep my pylon on a wall / corner, but not isolated. Zeratul rarely comes into play, however.
Merc compound – for upgrades and heroes, do not buy until fairly late, often times until you are at max supply,
Upgrades – damage upgrades are generally superior to armor upgrades, so with the exception of tanking units, it’s best to get several attack upgrades before any armor. It is occasionally worthwhile to get unit-specific upgrades earlier in the game, blink or stimpack, for example, but usually it best to wait until you have the 900 (or 450 if you have a lead and don’t want to game to go on much longer) banpei. I generally max out to 90 supply before getting my upgrades, but if you are going for a bunch of small units like marines, there may be no reason to max out, as they more marines would be less effective than upgrades.
All 3 of the heroes are generally worth their price, it’s just that Kerrigan tends to outshine the other 2. Her razor swarm does massive damage to ground and air, has great AOE, and her energy regenerates quickly. In expert level games, it often becomes a battle between Kerrigan micro.
Kerrigan - if it's a serious game, you're simply best off getting her. Wait for her energy to build near 150, and cast razor swarm on a large clump of enemy units. As long as she's regenerating energy, to use her defensively, it's best to wait as long as you can to cast razor swarm, as your opponents units will have generally clumped up more by then. Can cast it twice at max energy (75 per cast).
Odin is okay. He has a long rang AA attack, and his nuke and barrage are decent, but not nearly as destructive as kerrigan’s spells. If you are getting terran mech upgrades, you might consider Odin, as he will benefit from them.
Zeratul is very high-risk very high-reward. If you can slip by enemy detectors, and snipe off 1 or 2 pylons, then he is well worth it. However, doing so require decent micro/framerate/low lag, which is why he isn’t seen very much.
It is possible to wall off one lane with a vertical line of buildings, and this will cause fighting to occur only in one lane. The tricky thing about this is that if one side is forced to cannon, you can simply break one building the wall off, and force fighting back into the other lane, which is undefended. This doesn’t happen very often, but if you pay attention and notice that people are doing this, it’s best to mimic this strategy, and build counter units.
There are a great variety of units and unit combinations that can lead you to victory in Nexus Wars. Some units are almost unequivocally better than others, but what largely dictates how you should go about playing is what your opponent builds. Knowing how to react is as important as knowing what to build yourself. However, note that a good offense is the best defense. Becoming fixating on how to counter your opponent will likely muddle your own strategic mind. You must plan ahead, and you must anticipate your opponents' moves because the income mechanics Nexus Wars are compounding.
Classical strategies are among the most effective. E.g., bait and switch. Build one or several units that have are powerful in themselves but have a specific counter. If you've chosen a good unit (e.g., the lurker), you may be able to push unprepared opponents back outright. On the other hand, they may counter with banshees, in which case you can simply build queens. If you are successful in this endeavor, you will have put yourself in a good position. In short, if you know the game, your may spend your energy on knowing the mind of your opponent.
There are many, many things with which you can bait. In general, I find great success in baiting air units with my strong ground army, and then adding appropriate anti-air, so I can win both the air and ground fight.
Defenders advantage plays is a pretty big factor in Nexus Wars as well. If your opponent has built cannons, the best course of action is likely to pursue economy. There is effectively no reason to push without the intent of winning, unless of course it's some mind game.
That being said, putting on early pressure is one of the easiest and most effective things you can do early game. Then you can back off and outproduce your opponent later, after being ahead in pylon upgrades for sometime.
Examples of strong openers include...
roach + reaper AndOr sentry
stalker + hellion
firebat + medivac
zealot + marauder
...to name a few.
Unless you think you can win with these combinations, back off and build a pylon. Putting on early pressure can give you an edge, but most of the time it requires follow up.
Late game tactics
thor + carrier w/dingle support (quite resilient to kerrigan)
immortal + banshee + anti-air
thor + ghost
Add more in comments. There are a lot more.