Let me preface this article by mentioning what this article is not: This is not an exhaustive guide to every monster in Zelda: A Link to the Past, nor is it a comprehensive method on how each enemy class was designed. Rather, this article is really about how to design enemies by their functions using the example of Zelda: A Link to the Past. Most articles that discuss this topic often pick examples from various different games to give a better outlook on how this applies to different environments, but they lack a hollistic understanding of how gameplay mechanics and functions actually intertwine. The purpose of this article is to dissect Zelda: A Link to the Past's monsters to better understand how this specific gameplay can host mechanically different obstacles and what their impact is on flow and player decision-making. Note that we will not cover Bosses here, as they're an entirely different form of obstacle!

Game Mechanics & Resources in a Link to the Past

The first part of this analysis requires that we take a deeper look at the inner workings of the game so we can better understand how each monster was designed. This arbitrary breakdown of the game's 'pieces' is not absolute, but it should suffice to explain monster design by their function.

Life

Link's primary resource is his life. This is a measure of attrition that represents Link's ability to survive the challenges laid in front of him. The primary issue with 'dying' (running out of life) is actually a severe loss of time: though the state of the game is effectively saved, the player must restart progress from a distant location and needs to make his way back to where he was in order to proceed any further. Death is frustrating, and the player seeks to avoid it by any means possible (potions, faeries and, obviously, not taking damage). There is however no form of 'loss' associated with death. Causes of damage / death: - Bumping into enemies - Bumping into traps - Enemies' missile attacks (including Bombs) - Falling into pits

Magic

Magic is Link's ability to use some of its most powerful tools (magical items). It insures that Link pays careful attention to when and where such tools are used. Because most of these items cost a lot of magic and that magic is harder to come by than hearts, this is a critical resource in the game. Running out of magic is inconsequential in and of itself.

Bombs & Arrows

Bombs are an expendable tool that Link can stock up on and they can be used as soon as Link has at least 1 of them (no other tool is required). They are effective at uncovering secret areas. Their 'max' is limited. Arrows behave similarly with the exception that they require a bow to be fired (regular or silver). Bombs and Bows are very similar to magic, except they're much more specific.

Rupees

Rupees are the currency of the game, they can be found in various colors which are worth different amounts of currency. Rupees are only truly useful for two things:

• Zora's Flippers (a passive tool that grants the player the ability to swim)
• Potions (which can replenish life and / or magic) - mandatory for Turtle Rock in a regular playthrough

Every other use is optional (increasing maximum amount of bombs/arrows carried for example).

Time

Time is not an obvious resource in this game, but given that progress is not lost on death, time is the only thing that the game takes from the player. To a degree, dying in Zelda: A Link to the Past can be summarized as having to walk all the way back to where you died but being able to avoid most of the danger on the way. Essentially: dying is a loss of Time. Similarly, should the player ever need to build-up their rupee count (possibly to buy bombs, arrows, potions, etc.) or regain life, magic, etc., they can simply accomplish all of these by spending some Time in the less dangerous areas of the game. Thus it can be said that most resources can be acquired by spending time in the game, and that death results in a loss of time that could've been spent acquiring resources instead. Equivalently, the loss of resources is also a waste of Time with the exception that the effect is delayed. This toll only trully becomes apparent when the player lacks a specific resource to complete a dungeon, and must therefore go out of the dungeon to seek the missing resources. On most other occasions, that 'loss' is hardly felt as the player will come across resources naturally on their next trip through the worldmap.

Enemies in Zelda: A Link to the Past

The role of the enemy in A Link to the Past is to make the game longer by having the player spend Time. This is confirmed by the many rooms where the player is forced to kill all of the monsters to get the key or force the door open. The clear intent is to create an obstacle that the player must first analyse and then devise a plan to overcome. Each enemy's role is to insure the player will lose some time at key locations. The obvious approach to doing this is creating monsters that have progressively more life and deal more damage. Doing so however hardly challenges the player's ability to observe and react which, in practice, take a lot more time than simply becoming better at honing one's reflexes. If all enemies in the game were Sword Soldiers of varying strength, not only would the game become boring quickly, but it would also be much easier and faster to complete as whatever the player has learned to beat the sword soldier would apply to all other soldiers. So how, exactly, should monsters be created to enforce player observation and pattern recognition?

Enemy Types and Functions

Sword Soldier

Let us begin this breakdown by looking into The Sword Soldier: One might be led to assume, from the above, that the Sword Soldier is actually the most basic form of enemy in the game, but it isn't as 'Vanilla' as it seems. The Sword soldier has its own movement pattern and boasts one of the most interesting hidden features in the game: Stealth. Until a Sword soldier has been attacked or has seen the player, it won't actively pursue the player, which makes it particularly interesting to avoid. A lot of the level design actually supports this to great effect, but arguably, very few people ever went through the game without engaging combat with them apart from the SpeedRunner's community, simply because there is no incentive to doing this aside from time (which is a limited concern to most). In addition, the Sword Soldier is likely to drop rupees or hearts, which have some 'Time' value. In essence, you might just gain as much time from killing a sword soldier and getting its drop than you might gain by avoiding the fight altogether. Sword Soldier's Function = Get acquainted with combat mechanics and stealth.

Bow Soldier

By design, the Bow Soldier is a coward, which will not seek direct confrontation from upclose, but it is a terrific flanker. As a result, it makes positionning and movement all the more important to master, and its strength is relative to the other monsters in the room, and how hard it is to navigate said room. There is a specific room in Agahnim's Castle where the player must push a block while a few Bow Soldiers are looking at him, and it shows to great effect how much more powerful the Bow Soldier is when the room supports him. It can be impressive when first encountered, and its very complex movement pattern (moving away between shots when at melee range, taking orthogonal shots, etc.) takes a while to gauge appropriately for a new user, and more importantly, it scales in difficulty organically based on what features are impeding the player from getting up close and personal (tough melee enemies, obstacles). As a last resort, the player can use their own resources (arrows for example) to shoot them down, but they're hardly worth that resource investment, and thus pay for themselves. This is largely inconsequential to a player unaware of resources = time, but it is very real if said arrows are required later within the same dungeon. Bow Soldier's Function = Reinforce the player's understanding of movement and positionning. Also potential resource trap.

Enemy Checks

A number of enemies in the game act as secret 'gates' or 'checks'. Their purpose is often to confirm that you have the required gear to proceed. There are a few sub-categories (these are not canon terms, I merely employ them to better explain how they differ from one another): Soft Checks A soft check is an enemy that can be killed by conventional means but is much easier to kill by a specific method. The 'Green Eyegore', for example, is a great Soft Check. You can try to kill this hulking beast with sword alone but might lose a few hearts doing so, while a single arrow to their one eye will net you an easy kill. It is possible that this soft check involves resources, which basically punishes the player a bit for not having kept the necessary resources in inventory. For example, the 'Gibdo' in the Dark Forest is easier to kill using the Fire Rod (acquired in the same dungeon) but it implies having both the Fire Rod and magic. At the start of the dungeon, the player must deal with this enemy with their sword because they do not have the rod yet, and chances are that when faced again, the player may still need to resort to sword because they haven't been saving up on their magic. Soft Check's Function = Rewards the player for exploring the 'tool vs enemy interactions' & encourages the player to choose when and where to spend their resources. Hard Checks A hard check is an enemy that cannot be killed by any other means than the one it was designed to be killed with. The Terrorpin is a good example of a Hard Check. You cannot kill them unless you have the hammer. Generally speaking, this simply confirms that you went for the Big Chest in each dungeon and is an insurance policy from a level design standpoint. Hard Check's Function = Level Design tool to gate certain areas based on items acquired without having to create a hard lock (such as Titan's Mitt) & 'Puzzle' element where the player needs to experiment with their tools to see how to dispatch of certain enemies. Hard Resource Checks A Hard Resource Check is an enemy that cannot be killed by any other means than the one it was designed to be killed with, and that method involves a finite resource. The 'Red Eyegore', for example, is a great Hard Resource Check. You cannot kill it any other way than shooting two arrows to its one eye. If you run out of arrows, and this enemy must be killed (for a key possibly), you're screwed. THIS is when you feel the loss of time induced by spending/losing resources. To get these 2 arrows, you'll likely need to go out of the dungeon which may take just as much time as dying. Other notable examples of Hard Resource Checks include the Freezor which must be killed by using the fire rod (and thus, having sufficient magic left). It is what keeps the ice palace locked (until the dark forest level is completed). Hard Resource Check's Function = Punishing player for spending resources unnecessarily.

Stalfos Knight

The Stalfos Knight is an interesting enemy: it keeps coming back! Though hinted at in a previous room, its actual flaw remains hidden to the player. It is an enemy that keeps the pressure on the player and forces them to explore the possibilities. It is actually a Hard Resource Check in that it requires a bomb to kill, but it is also a very unique obstacle in that it is a two-stage enemy which requires an added level of exploration from the player. Stalfos Knight's Function = Rule breaker: it causes surprise to a well-executed plan and requires further investigation / experimentation. Also good to punish players for spending bombs unnecessarily.

Helmasaur / HardHat Beetles

The Helmasaur and HardHat Beetles are related in that they both change the rules of engagement and have an effect on the player's positionning. The Helmasaur charges the player headstrong, and typically cannot be harmed from the front which forces the player to find a means to flank it. It is also an enemy that does not deal a particularly high amount of damage, but seeks to push the player into holes or other traps. The HardHat Beetles have a similar role, but defensively. It punishes the player from engaging in melee combat by having them bounce backwards (possibly into a hole). Helmasaur & HardHat Beetle's Function = Challenge the player's understanding of melee combat (flanking, knockback) and demonstrate synergy between environment and monsters (holes).

Vulture & Mini-Moldorm

The Vulture is not a particularly interesting enemy, it's actually rather annoying, but it serves a purpose. Because of its flight pattern (circle), it is very hard to determine the angle in which it will try to attack the player. Similarly, the Mini-Moldorm has a rather erratic movement behavior making it particularly hard to predict how it will bounce off walls. Both of them are particularly hard to hit with ranged weapons and generally require tough reflex-based close combat or the use of the spin-attack. Vulture & Mini-Moldorm's Function = Reward players with good reflexes and / or usage of the charged spin-attack.

Red Stalfos

The Red Stalfos is a simple critter, but with a twist. Unlike the blue Stalfos which behaves essentially like a Sword Soldier minus the 'chase after the player' pattern, the Red Stalfos also punishes the player for inaccurate strikes by throwing a bone. Most enemies don't give a rat's eye whether the player hits or miss an attack. The Red Stalfos' role is to teach the player exactly how their sword behaves and have an understanding of its actual reach. Obviously, in the event that a player should spend highly valuable resources, the Red Stalfos pays for itself through attrition of player's resources. Red Stalfos' Function = Punish player inaccuracy or punish player for spending resources unnecessarily.

Hoarder

The Hoarder is a small bush-like enemy which isn't actually an enemy. It is a rule twister that forces the player to reconsider his understanding of the game rules and may lead the player off-course to chase after him. Hoarder's Function = Play with the player's mind! (He doesn't hand out that many rupees to be honest!).

WallMaster

Assuredly one of the most dreaded monsters in the game, the WallMaster is a giant hand that falls from the sky to capture the player and force them out of the dungeon. Purposely, he first appears in a dungeon (Dark Forest) where each segment of the dungeon is rather small, and being kicked out is less frustrating than a regular dungeon. It's primary function is simple: it kills you without killing you. Essentially, it drops the 'I need to lower your life points to 0 to force you out of the dungeon' to, 'I need to hit you to force you out of the dungeon'. The actual time loss is shorter, but the WallMaster is clearly the deadliest monster despite not actually dealing the player any damage. The WallMaster also serves a secondary purpose: it forces the player to move based on repeated stimuli (falling sound, and growing shadow spot). Though he is easy to dodge under most circumstances, he does some area denial for the player, which in conjunction with other monsters, can result in very challenging environments. More importantly, the WallMaster does not give you much time to think. You quickly understand what he does the first time he catches you, but that doesn't stop you from having to study the 'rest of the rooms' you enter, and he denies you the ability to analyze the room in great detail and devise a plan. The WallMaster's true function is to insure that you must multi-task: use what you've learned in terms of movement and positionning to keep moving about, hoping to dodge most threats, all the while having to think about what the room needs you to do and how you're likely to do it. It is the greatest time killer in the game! A much weaker variant of this approach exists as the 'Thief' which tends to steal mundane resources (rupees, bombs, etc.) instead of dealing damage. The loss of time is marginal compared to the WallMaster's unique behavior. WallMaster's Function = Force the player to lose focus and make mistakes.

Applied Process

This section suggests a possible approach on how to design enemies by their function in a game such as Zelda: A Link to the Past.

Step 1: Determine Resources

The first thing we did in this article is list out the resources of the game. They were listed so that the following section could be understood, but it is also the first step to creating enemies that are relevant to gameplay. In the above example, it turns out everything can be equated to Time more or less. Once this is confirmed, the designer's role is to understand how they can affect 'everything' in different ways. It was listed above that the loss of resources could be as problematic as a loss of time, and key scenarios could potentially lead to situations just as bad as death without actually interacting with life.

Step 2: Identify a Scenario and Define the Required Functions

One such scenario is being faced with a mandatory enemy which is a Hard Resource Check and being short on this specific resource at that given point in time. To create such a scenario, at least 2 enemy types must be created:

• An enemy that acts as a Hard Resources Check (say, the Red Eyegore)
• An enemy that is either a Soft Check for the same resource (Green Eyegore) or a Trap enemy (Red Stalfos / HardHat Beetle) which does not specifically need the same resource to kill, but whose effect might lead a player to spend their resources unnecessarily.

Step 3: Design Enemies Based on Required Functions

The first enemy is easier to design, as its sole purpose is to be impervious to attacks save for 'the one' (in this case, arrows). However, it should somehow hint at its weakness so that the player does not immediately rush in unknowingly. The Red Eyegore is a great fit because it is possible to have the player experiment with the Green Eyegore first and learn the hard way that the arrows are a better bang than the sword without actually dying unable to do a thing. The second enemy is more tricky because it needs to be tough but not impossible to kill without the use of said resource. The Green Eyegore is a good fit because it is actually impervious to arrows from afar, forcing the player to interact with it and investigate means to kill it (knowing that a swordfight is not desirable). You'll notice that, in the game, the Green and Red Eyegores both show up in the same dungeon originally, and there are a few Green Eyegores leading to the mandatory Red one. This is the realization of a function-based enemy design segment within the game. The expectation is that the player will reach this point with enough arrows to successfully proceed, but that the quantity of arrows left will be sufficiently low that the player will have some form of realization of just how important arrows are, and how dangerous Red Eyegores can be. This creates a reference from which players are likely to learn to save up on resources so they don't end up frustrated later when they need to back out of a level by lack of resources.

Step 4: Rinse / Repeat / Remember

Applying steps 2 through 3 repeatedly can create interesting twists, Scenarios can be anything that looks interesting, and enemies need to be designed to support this desired outcome. The WallMaster, for example, is a single enemy which acts as the realization that it is possible to kill the player without killing them by effectively creating similar consequences (forcing the player out of the dungeon against their own will). It's also interesting to bear in mind all of the scenarios created during Step 2, and what effect they might have on one another. Simply creating new scenarios may lead to a clutter of enemy types that may not work well with one another for various reasons. Sure, the level designer has these tools and is not forced to use them, and each dungeon is a separate narrative that they have full control over, but it is still better to have monsters that are functionally coherent and redundant. In other words, if you have one way to create shortage of resource and you want to create another one, it better be a drastically different approach, or a 'reskin', not something mechanically similar.

Conclusion

Creating monsters by their function is a wide topic and isn't an exact science. True experience is acquired in the field with applied examples rather than generic formulae. This article attempts to slice through one game's core monster designs principles to create a point of reference, but it, by no means, suggests that it covers everything there is to know about functional monster design. Afterall, much like other design crafts, Enemy Design is an Art.

Article Update Log

3 Aug 2015: Original Draft 26 Aug 2015: Release 27 Aug 2015: Revised template / structure