Introduction
Strategy games are one of my passions, and Zero-K remains one of the greatest RTS games I have ever played. The depth of strategy combined with a user interface that makes it simple to project my strategy and tactics on the battlefield are unparalleled. Having played for a few years now, I wanted to express some of my thoughts and observations about the game in a form that I could share with others. This essay is my attempt to explain some of the principles of Zero-K, how to understand the roles of different unit classes, and finally how these principles and concepts work to create a strategic plan in both 1v1 and team game contexts.
Principles and Goals
The goal of a game of Zero K is Complete Annihilation of every one of your opponent’s units and structures. You begin the game with only a single commander, a formidable combat unit in the early game. Attempting to win the game with just this unit, however, is going to prove nearly impossible. Your opponent also has a commander so at best you will trade commanders into a draw. Instead, your commander should be used to begin building up your forces. With numerical superiority, your ability to overwhelm and annihilate your opponent improves until eventually victory is assured.
So how do you ensure that you are the one with greater forces than your opponent? You start by using your resources to create units and structures. The more resources you have access to, the faster you can construct additional forces. Expansion becomes your first sub-goal on your path towards victory, because expansion gives you access to more resources. Every metal deposit on the map should be your objective, increasing your income to maximize the strength of your army. It is equally important to spend these resources, so ensure you have the energy and build power to do so.
A strong opponent is no fool, so they will likewise seek to expand and increase their income. Inhibiting their growth is your next priority, preventing them from amassing an army to rival your own. Early harassment of their constructors is an excellent way to slow your opponent down.
Finally, to ensure that your forces will eventually dominate your opponent, you want to trade forces favorably. Keep your units alive while whittling away at your opponent and even on equal economic terms you will soon be able to crush your opponent with sheer numbers.These three sub-goals are the key to success in Zero-K. Grow your economy, stifle your opponent’s expansion, trade forces well, and your opponents will fall before you. Neglect these principles, and you may soon find yourself facing insurmountable odds before your eventual defeat.
Unit Classes and Roles
RTS as a genre requires players to execute their strategy, and often it isn’t straightforward to go from a list of abstract goals to an executable form. Zero-K is no exception, with dozens of units to choose from when constructing your forces. Which units to build and how to use them to achieve your goals is often something that must be learned through experience. There are some guiding principles regarding unit roles, however, that can help build a mental model for how the battlefield of Zero-K works. Comprehending the basic unit class triangle of Raiders, Riots, and Skirmishers is foundational to understanding how to choose and use your units well.
The first category of units to look at is Raiders. Raiders are the embodiment of the principle of unit presence. These units are intended to occupy territory, destroying your opponent’s forces by finding places where you outnumber their forces and using their high mobility to reposition and take advantage of gaps in their defenses. They also secure your own territory by counteracting your opponent’s Raider presence. By simply existing in the right place, a single Raider can wreak havoc on your opponent’s undefended economy. These are the first units to look at as a way to achieve the first and second subgoals mentioned above. A force of Raiders can slow, halt, or even reverse your opponent’s expansion while protecting your own constructors from your opponent’s schemes.
Riots are often considered the counter to Raiders. While this is an acceptable approximation, it ignores the role that Riots are intended to perform. Riots are used to control territory. Their high DPS ensures that anything in range dies quickly, making the area around a Riot safe for your other units and structures. Their slow speed means they can’t rapidly reposition to find weak points like Raiders can, but their ability to control the area around them means they can be difficult to remove. This can be leveraged to punish an opponent who lacks sufficient territory control with their own Riots by just walking your forces into their base.
The final class of the early unit triangle, Skirmishers, is less obvious to assess in terms of their role. What Skirmishers do best is to deny your opponent access to territory. With longer range they can attack and retreat safely, inflicting attrition on shorter range units. This ability to deny your opponent’s forces a safe place to stand comes at the cost of an inability to control their immediate vicinity. Raiders that can quickly cross the range of the Skirmishers will ignore this area denial by not remaining in the area for very long. Riots aren’t so lucky, as their lower speed means that area denial from outside their range of control means they find themselves useless against aggressive Skirmishers. It’s important to note that the role of Skirmishers isn’t defensive in nature. With no ability to control territory, they must retreat when pressured. Trying to defend your base with Skirmishers when your opponent has Riots at your front door isn’t going to prevent them from walking in and destroying everything.
Defensive turrets often fill a similar role to Riots. Turrets control the area around them by offering cost-effective damage and enough range to prevent enemies from closing the gap without suffering losses. Turrets lack the ability to pose a threat to your opponent since they are static defenses, but when you need to add more control to your territory they can quickly fill that need. The exception here is the Picket, a turret that behaves much more like a Skirmisher. This low DPS but high range turret is primarily used to undermine your opponent’s turrets, denying them territory but not controlling its own.
These three unit classes can be described by their focus on territorial acquisition(Raiders), control(Riots), and denial(Skirmishers). When making choices about which units to build, consider your plans. Perhaps you’re expanding slowly under pressure from your opponent, and need to build Riots as part of a slow-but-steady plan to keep control of your expansion. Maybe you’re on the offense, and need to add some Skirmishers to keep up the pressure and deny your opponent safety behind turrets and Riots. Choose the right unit for the circumstances, not because it counters the units your opponent made, but because it’s the right unit for your own plans.
Transition and Role Evolution
As a match of Zero-K unfolds, many elements of the game start to change. Both sides have accumulated more resources, and the forces on either side have grown larger. The landscape of the map has changed as well, with terraform and the position of both armies and defensive structures impacting how the shape of the map looks from a strategic perspective. These changes impact how the roles of Raiders, Riots, and Skirmisher behave, forcing a transition from players and evolution of the roles themselves.
With an increased density of defenses, Raiders begin to face difficulties fulfilling their roles. There are few relevant places that lack sufficient enemy control for Raider presence to take territory. The mobility of Raiders is negated by there simply being defenses everywhere. To make headway in a game with far more control, Raiders must evolve into Assaults. Assaults have the same goal as Raiders, in that they seek to occupy territory and exploit weak points in the opponent’s defenses. Rather than mobility, however, they rely on a larger health pool to survive the opposing control in order to remove valuable targets or simply occupy and remove the enemy forces present at the location. Assaults retain some of the Raider ability to resist area denial by enemy Skirmishers, but some of this is sacrificed as the Assaults often lose the speed to chase down Skirmishers.
Riots retain much of their value in the more dense and higher control environment of middle-late game Zero-K. The main threat they face is area denial from Skirmishers, and as density rises so does this threat. An evolved form of Riot is necessary to retain regional control in the face of Skirmisher threats. This evolution is the Porctress, derived from Porc as a common term for defenses. The Porctress is a combination of turrets, shields, and terraform designed to resist an opponent’s attempts at assault or area denial. A Porctress exerts tremendous control in a much larger area than Riots, but at the cost of all mobility. When considering the strategic goals of expansion, denial of enemy expansion, and favorable trading, a Porctress only loosely denies enemy expansion. Immobility renders its contribution to expansion null, and the opponent generally does not need to trade forces into the Porctress so no attrition is gained. Still, the Porctress grants safety to the final component of the evolved unit triangle, and in a position of economic parity this allows the Artillery to whittle down your opponent.
Artillery serves as the evolution of Skirmishers, improving their role of area denial through more range and damage. With the improved control afforded by higher density and the Porctress, Artillery no longer needs the mobility of Skirmishers. Artillery also serves as the tool needed to soften an opponent’s Porctress for an eventual assault. This now finally starts addressing our original goals more directly, denying enemy expansion through area denial and winning a war of attrition as the Artillery bombards the opponent from range. With sufficient control to repel Raiders at higher game densities, Assaults become one of the few options left to remove Artillery.
It’s important to note that while each of these evolved roles is more effective in some ways than their early game counterparts, they depend on the density of forces and higher scale economies that the latter game of Zero-K typically presents. Rushing to build a Porctress neglects expansion and is too slow to deny your opponent’s expansion. Early Artillery means you lack the control necessary to keep it alive. Assaults are too slow to keep up with enemy Raiders, and their strength in resisting area control has little benefit when there is little present to resist. Continue to keep your goals in mind, and use those to guide you when it is finally appropriate to begin transitioning to the evolved unit roles.
Hybrid Unit Roles
A number of units can serve multiple roles, requiring special care to make sure they are being used in the correct way. Some of these are more apparent than others, but generally their roles must be evaluated individually. A few of these will be listed here, and the rest left as an exercise for the reader.
Riot-Raiders come in a few varieties, but they are the simplest to understand. Somewhere between Raiders and Riots in terms of both their mobility and their ability to control territory. For factories that have Riot-Raiders, they can offer flexibility when it isn’t clear whether you are the aggressor or the defender. Offensively more of a Raider, defensively more of a Riot, these units can offer a smooth transition by mixing them into your forces as your economy permits.
Grizzly acts as an Assault-Skirmisher, denying enemy forces safety at Skirmisher ranges but with a health pool large enough to aggress into enemy controlled territory to pick off weak or valuable targets. Like both individual roles, the Grizzly lacks the ability to control its immediate surroundings because of its low fire rate and is vulnerable to being overwhelmed by sheer numbers.
Knights are an Assault unit that has much stronger control than most, making it almost a hybrid Riot-Assault. Too slow to really survive concentrated defenses or Skirmishers, it is often paired with area cloakers to make use of its strong controlling capabilities when it can close the gap safely.
Fencers are predominantly Skirmishers by role, but their ability to actually exert control in their proximity makes them a powerful hybrid. They exhibit Raider-like tendencies in their ability to claim new territory, their low cost and high mobility playing a key role here.
Conclusion
You might ask why it’s important to understand the different unit roles when it comes to Zero-K; it seems simpler to just treat the roles as a rock-paper-scissors triangle, reacting to the opponent’s choice with the right counter. The flaw in this philosophy is that it leaves you in a reactive position, with your opponent dictating the pace of the match. Responding to your opponent’s Raiders with Riots immediately is the “correct” counter, but neglects your objectives on the path to victory. Slow defensive units grant your opponent the freedom to expand rapidly, quickly outpacing you economically and rendering any advantage your “counter” provided impotent. Reactive play prioritizes survival, and simply surviving doesn’t bring you any closer to victory.
To emerge victorious, you must play to win. Focus on your own goals of expansion, harassment, and efficient trading. Consider your current objectives and pick the units that best match the plans you intend to put in motion. Don’t ignore what your opponent is doing, but don’t let yourself get wrapped up in reacting to their play. More advanced strategies and tactics will come as you gain experience, but sticking to these basic principles will give you a solid foundation to build upon.
