Typical game progression

This is a guide explaining how a typical game progresses, after a typical opening. The game can be thought of as being organically split up into a few phases, each with a characteristic set of units and goals.

• Note that these are general scenarios - depending on the map and factory match-up the game can play very differently!
• From a 1v1 perspective
• (wip)

Raider phase

The raider phase is the first phase in a typical game. It is defined by a few characteristics:

• Most of the map is unoccupied by either player.
• No defenses covering most areas.

Due to this, the mobility that raiders have tends to make them the dominant unit class. When the map is fortified with light defenses, raiders are much less useful and it will be time to switch to something else.

Expansion

You will want to expand as fast as possible here, and try to grab at least half of the map. Try to have two groups of constructors moving around the map taking mexes. Near each mex cluster you can put some light defences, but do not overbuild defences early game, and in non-critical locations (i.e. not a choke point or the centre of the map). Run around the map with your raiders, keeping track of where your opponents raiders are as well.

You should be able to defend your expansion from enemy raiders with some light defences and some of your own raiders. Since raiding properly is considerably more difficult than expanding, you should be encouraged to expand as fast as possible.

• Try to expand much faster and in a more risky manner than you think is possible for a few games. You might be surprised at how much greed you get away with! It is much harder to punish greed than it is to be greedy. Doing this will also help you learn the safe maximum limits for expansion.

If you succeed in this phase of the game, you will have a massive economic advantage and will be able to build more units.

Energy production

A very common mistake players make is that they don't build enough energy structures. This leads to a situation in which your metal income exceeds your energy income and you are unable to spend all your metal (called "e-stalling"). Having 1 constructor dedicated to only building energy structures can solve this issue.

Raider Usage

You want to have good radar coverage of your side of the map and keep your raiders as close to the enemy as possible. This puts pressure on them, and also forces them to keep their raiders near their base, away from your expansion. Against good players you will not be able to do much damage with raiders, but that does not mean you have accomplished nothing by keeping your raiders near them.

• Because of the threat of your raiders, they are not able to "naked expand" (expanding with minimal defence). If you allow your opponent to naked expand, they will have a massive economic advantage.
• Your opponent is forced to keep their own raiders near their own base to defend from yours. It can also force them to build more defences, slowing down their expansion and reducing the amount of pressure they can put on your own expansion.
• Your raiders are also scouting. By running around at the edges of your opponent's territory you will be able to see what they are up to. If they are trying to rush a heavy unit or do something silly you will often just be able to overrun them and win.

If you find yourself on being the one that has raiders at their front door, things are a little more challenging, but don't panic.

• Try to expand where your enemies raiders are not (with that other group of builders on the other side of the map that you have...right?).
• You can slowly creep forward with LLTs and the protection of your own raiders.

Note that you do not need to kill anything to have a successful raider phase. Your primary goals are to expand and grab territory while slowing your opponents expansion to a reasonable pace, and also have the energy to use all the metal you took control of. Your raiders will be useful later, so try to keep them alive. There is a "reasonable maximum speed" at which players can safely expand, and as long as you make sure your opponent doesn't exceed this and you are close to it, you will probably enter the later stages of the game on equal footing. Few games are won in the raider phase, but the tone of the rest of the game is set by it.

Fortified areas

You may see a location that is lightly defended with towers, and you will correctly assume that you can run into it with your raiders and kill everything. However, this is a risky (and often unnecessary) thing to do.

• There might be some defences you don't see, like nearby units lying in wait.
• Killing towers with raiders is not cost efficient, so the payoff might not be that good.
  • This could lead to your opponent taking a temporary raider number advantage, which could put you on the defensive and actually put you behind from where you were before, as you are no longer able to exert as much map pressure.
• Committing your raiders to an attack like this open you up for the possibility of a counter-attack, and since your raiders are somewhere else, you might not be able to defend well.

Finding a lone commander

Sometimes your opponent may be too greedy and have their commander out alone. Likely it is low level, and a moderate amount of raiders is enough to kill it. A fallen commander is a crippling blow to the victim's economy. Some raiders are better than others at this job.

• Spread your units out right before it dies, as they have a death explosion which could wipe out your raiders if they are really close to the commander.

Why not other unit classes?

Riots

It may seem intuitive to make riot units in this phase of the game. "They're good against raiders, aren't they?" you may say (correctly). However, there are multiple downsides to using them.

• They are very slow. This makes them unusable for attacks, as your opponent will see them coming and be able to easily respond. They also cannot respond to attacks.
• Early game, lone riot units can be overwhelmed by raiders.
  • For this, a concave line formation is highly effective, to minimise AoE damage from the riot unit.
• Light defences are effective against riots, as riots are DPS, not HP focused. Light defences will take a significant portion of the riot's HP away before the riot is close enough to fire. What usually happens is that the riot kills one or two defensive towers and then dies, which is cost-inefficient.
• Riots can be outmanoeuvred and ignored. Because of this, players tend to spread out their riots to try to cover every location so you can't run past them, which also makes them easier to destroy piecemeal as above.

Because of the above reasons, they do not pose much of a threat, except in circumstances such as a riot rush, but you should've scouted that.

The correct way to deal with an opponent making riots is to just expand faster than they do - they won't be able to punish this. When you inevitably get a superior economy, you can just overwhelm them.

Any other class

Skirmishers, artillery, assaults - all of these do very badly against raiders, so are not worth building at this point.

Importance of radar

Radar coverage is very important to get in this phase. If you do not have it, you have to play defensively in case your opponents tries to raid some of your expansions. The alternative is building lots of defences everywhere, but this is a losing strategy, as it leaves you unable to punish your opponent for expanding. If they expand they will just overrun you with units.

By building radar you can reduce the amount you spend on defence, and can use it on offensive units instead. In the worst case scenario, you prevent greedy expansion from your opponent. In the best case, you just win because they were too greedy and have no units.

Dealing with defensive players

A strategy that many have trouble dealing with is when your opponent just builds lots of defences at every expansion site. The best way to deal with this is to just ignore them and focus on expanding yourself. If they want to sit in the corner building defences, that is fine for you. This is essentially saying that they want you to come to them. Eventually you will.

Since they have spent so much metal on building defences, they won't be able to prevent you from expanding, and they can't expand themselves. Take the whole map and build your economy. Only then will you come to their base and crush them with artillery, heavy units... probably a strider or two.

Remember Sun Tzu - "A general who attempts to bolster his defences everywhere will quickly find he has no defences anywhere." No one can build a line the enemy cannot pass.

End of raider phase

Eventually, the map will become covered with a line of defences from both players, partitioning the map roughly in half. This limits the mobility advantage that raider have, and it becomes time to switch to something else. Some areas might be lightly defended, and if you know the enemy's raiders are not close, you can punish this. However, by this point people often have full radar coverage and they will be prepared.

Midgame phase

In this phase, strategic diversity opens up significantly. Players typically transition out of raiders into some of the following:

Skirmishers

A common strategic switch people make is a shift to building skirmishers rather than raiders. These units are capable of killing light defences fairly well, so you can start pushing back your opponent and try to grab more territory. Use your raiders (which are hopefully still alive) to protect your skirmishers from harm. It is also common to see a few riots dedicated to protecting your skirmishers.

Assaults

For some factories, it is possible to switch to assault units. These units will be able to punch through light defenses (unlike raiders) and do some economic damage to your opponent. Some examples:

• Thuglaw - Outlaws and Thugs - this combination from the shieldbot factory is a very potent assault force. It is good against raiders and light defences, giving it the potential to do lots of damage to an unprepared opponent.
• Ravagers - Fast assault rovers that can be used for raiding. They are able to eat through light defences, and due to their speed it is harder to position raiders to defend against them.

Air units

One area people often neglect is the sky above them. Air units are typically quite a bit faster than ground units, and bypass difficult terrain. There are many advantages to air units, with each type of air force having their own.

There are two air factories, which play very differently from each other.

Airplane Plant

Airplanes are fast and focus on alpha-striking the enemy. The Swift and Raptor are interceptors, able to defeat other air units. The four bombers, the Raven (precision dive bomber), the Phoenix (napalm bomber), the Thunderbird (disarming lightning bomber), and the Likho (high-damage AoE bomber) are in-and-out units, striking fast and hard.

The Owl and Sparrow are spy planes, able to scout the enemy quickly. The former can patch up any radar coverage holes, and the latter is an early scout which can be morphed from a Radar Tower. The Swift can double as a base scout, using its speed boost to quickly pass over an enemy base.

Gunship Plant

Gunship units are a slower than their air counterparts, and they also are DPS focused, instead of alpha focused like planes. They are mostly close air support, with the Nimbus being typical - delivering fire support from a distance.

The Charon and Hercules are notable as they are not gunships at all, with the former not even being armed. Rather, they are transports, boosting your units' mobility and taking them over any terrain. With an Iris, they can also be used for stealth infiltration.

Playing against air

First things first - radar coverage. radar Towers, Advanced Radar, all that good stuff. Can't fight what you can't see.

Get some dedicated anti-air units and buildings. Each factory has a dedicated anti-air unit - the Airplane Plant has two. There are also five anti-air buildings, which are also highly effective.

Fortification

In the midgame, players will sometimes fortify certain locations on the map with heavier defences such as Stingers or Stardusts. This happens at central locations of the map as it gives you a sort of staging point that you can keep your units at safely. Heavier defences generally require a response from artillery or heavy units, so by building some, you can buy yourself some time as your opponent is figuring out a way to deal with the heavy defences.

Stingers are especially tricky at this part of the game, as they are the first type of tower that can fight skirmishers well. If you find yourself losing ground to skirmishers or expect them soon, it may be a good idea to put up a Stinger. Stingers do not do that well against lots of light units, so make sure to keep building lots of LLTs (or even add a Stardust).

Lategame

Both players with have built up sizeable armies of skirmishers/riots/assaults and will probably have some air presence. The map will be more fortified, and it will be difficult to make progress with light units.

Eco

If things have stabilised in the midgame, it may be time to build your economy.

• Build on all the available Geothermal Generator spots. If you feel that some are very safely located, upgrade them.
  • Advanced Geothermals will often pay for themselves within just 3-4 minutes. As a bonus, they explode violently on death. If the area is clear of allies, they can make for a nasty surprise to nearby enemies. When followed by a quick reclaim and rebuild, this will give an additional boost to your economy at the cost of your opponent's.
• Connect your mexes into the Overdrive grid. The more mexes you connect, the more efficiently energy will be distributed, and you will end up with more metal. Overdrive is very efficient at low levels of energy, but suffers diminishing returns.
• Build Fusion Reactors. Make sure to scout before starting, as it can stop your unit production for a minute or so. If for example you scout your opponent switching to air or preparing a massive raid, it may be better to make sure you can counter their strategy before building it, as otherwise your efforts may be in vain.

As with expansion, it is much harder to punish greedy economy building than it is to do it yourself. Try to be a greedy as possible and learn what the safe limits are.

Heavies

At this stage in the game you will start to see heavies coming out. "Heavies" are units that are generally 1500+ cost. Most of them massacre the lighter skirmisher/assault/riot balls that are predominant in the midgame, and they also can stand up the to defences built in the midgame such as Stingers and Stardusts. These heavies are usually in the form of Tanks.

Bot specialist units

The bot factories do not really have "heavies", but they do have more expensive upper tier units that can be used to fight heavies of other factories.

• Cloakbot Factories will start to build snipers and area-cloakers.
• Shieldbot Factories can build mobile shield generators.

Light striders

Someone putting down a Strider Hub and making either a scorpion or dante is quite common.

• Dante is very good against skirmisher balls as its incendiary missile ability (the "D-gun") is highly damaging and deals AoE napalm damage. It is also one of the faster striders so it can get into action quickly. Due to all its AoE damage, it massacres riots and raiders as well. It fights assaults decently, but it actually loses to most of them by cost. You need to retreat and repair it to get full value out of it.
  • Be careful with your own units around the Dante. Dantes can deal friendly fire, and burning your own army is not a good thing.
• Scorpions are invisible and have their EMP ability. This can be used to sneak up on valuable targets like Commanders or a bunched up set of units, stun them, and then kill them. Scorpions are a support/assassination unit, as their DPS is much lower than a Dante, and also get kited by skirmishers easily.
  • Scorpions beat Dantes quite easily, especially if the Scorpion can stunlock the Dante.

Late-Lategame

In this phase you will see heavy striders and some of the more exotic tools available to the player.

• Big Bertha, the biggest conventional artillery gun in the game.
• Trinity, a strategic nuke silo.
• Ultra-heavy defences:
  • Desolator, a small fortress in the form of one building. Often put on a terraformed tower.
  • Lucifer, a sniper tower. Effective against large units.
  • Cerberus, a triple-barrelled mid-rage artillery emplacement. Used as counter-artillery or as area-denial.
• Paladin/Detriment, the two biggest striders in the game.
• Starlight, a constant satellite beam of death.
• Zenith, a superweapon which controls meteorites to throw at the enemy.
• Disco Rave Party, an artillery weapon which fire six different shots at the enemy in sequence, with different effects.
• Singularity Reactor, the biggest energy generator available.

Most games do not actually get this far, but the objectives remain the same, even if the whole battlefield is a smoking crater.

Conclusion

Note that this is a general overview. Sometimes people may rush with heavies in the midgame, or try building their economy during the raider phase. Zero-k is a very flexible game, and there is no set meta-game like in Starcraft 2. Lots of game play is map-dependent or match-up dependent.

But as always, remember that this is a game, so have fun and get out there!