Analysis of Gating Design in Super Metroid

(Source: Nintendo.co.uk)

Brief Intro

Super Metroid is a 2D pixel side-scrolling action-adventure platformer. It is a classic game that was very innovative at its time for its exploratory gameplay supported by thematically connected areas, intriguing player paths, and the trick behind the non-linear gameplay -- Gating design.

Gating is an obstacle, either an explicit or implicit one, that prevents players from entering or leaving a certain area. If the player is allowed to freely explore anywhere across the levels without restrictions, there will be no fun. Thus, this analysis will focus on what gating is, and how gating is implemented in Super Metroid.

⚠️Disclaimer: The gameplay screenshots are either taken from my own gameplay, or from an interactive map site (Link).

Gameplay Structure

Before the gating design is analyzed, it is necessary to briefly introduce the gameplay structure on which its gating design is based. Super Metroid has an item-ability dependency system. Ability upgrade requires item acquisition while the unlocking of a certain item is often dependent on the unlocking of another. To get item B, players need to unlock item A to open the gate. To get item C, players need to unlock item B, and so on.

Thus, the sequence of the items to be acquired has formed a dependency chain. Below is a diagram of the item dependency I made:

The main purpose of the gating chain in Super Metroid is to prevent players from getting certain items too early by preventing players from entering certain areas, so that players will traverse the levels with proper challenges as their abilities grow stronger in a scalable and well-paced fashion.

Types of Gating

There are two types of gating: hard and soft.

Hard Gating

Hard gating is an explicit obstacle that uses common concepts to inform players that this entry is not instantly navigable, such as a door, a fence, or a pile of heavy rocks -- they are concrete objects that block your way. To open such a hard gate, certain conditions must be fulfilled.

There are four different types of conditions:

1. Item-based conditions: the most common item to open a door is a key. Other options such as a crowbar, an ax, a hammer, a bag of dynamite can also help if violent solutions are accepted in the game.

2. Ability-based conditions: players utilize certain abilities to clear the obstacles. It could be casting fire to melt a frozen gate; or manipulating water to extinguish a fire gate; or projecting magnetic fields to attract or propel a metal gate, etc.

3. Action-based conditions: some gates remain locked until certain actions have been done, for example, killing the boss in this region, killing the nearby enemies, or getting naked under a blood moon to make a shrine rise (Ask Link, he will tell you how).

4. Event-based conditions: some gates only open upon certain occasions. For example, a gate will open during a full moon. Or a gate can be snuck into when the enemy guards are asleep.

Hard Gating in Super Metroid

How is hard gating implemented in Super Metroid? In this game, there are three types of hard gates: doors, blocks, and tunnels. They are very straightforward.

Doors

In Super Metroid, there are actual doors to block players. These doors are placed at one end of a locked area. Doors with different colors indicate different conditions.

Example 1

Above is a partial screenshot of Brinstar. If the players have Super Missiles but not Power Bombs, they can unlock the green door but not the yellow door.

Example 2

The one-way openable metal poles above show that players can’t open them unless they go to the other side, because projectiles shooting toward the button will be blocked by the pole. Also, a pole with a green button requires a Super Missile.

Example 3

Players can’t open the metal door when the boss hasn’t been defeated. Only after the Boss is dead can players enter the treasure room.

Blocks

Example 1

Here are walls made of blast-open blocks. Players set Bombs to get rid of them.

Example 2

This is an example of pit blocks. These metal blocks are like a reversed version of jump-thru platforms. Players would drop to the bottom if they land on top of the pit blocks, and can’t go upwards once they drop.

Example 3

These concrete blocks can’t be moved or blasted when players are at normal speed but they melt away when players use Speed Booster to activate high-speed dashing.

Tunnels

Example

The water tube above is a special gating existence. Players in the tunnel are only allowed to traverse horizontally but not vertically.

Soft Gating

On the other hand, soft gating is an implicit barrier that keeps players from entering somewhere. Players might not realize that the entry is blocked until a few trials and failures that make them confirm that they lack something to pass.

Soft gating is usually created by placing the entry out of players' metrics or capabilities. Entries could be gated by some unreachable structures that are too tall for the player to jump onto, or too slippery for the player to stand on, or too wide for the player to jump across, or too deep for the player to swim. The idea is to persuade players to obtain a certain ability or item and come again.

Soft Gating in Super Metroid

Soft gatings are less obvious to notice right away. Here are a few interesting examples.

Example 1

Above are a few times players encounter a one-tile wide passage during their early stages. However hard players try, they can’t fit into that narrow tunnel. Then, players might think: “I need to either expand the tunnel or shrink myself in size.” As they keep exploring and wondering how, they encounter the first item, Morphing Ball that helps them pass.

Example 2

This is an example of how soft gating locks the players in an area. Players enter this area by the narrow tunnel (see #1), and they ought to enter the left room to get the Hi-Jump Boots (#2). Then they jump onto the platforms (# 3) and leave this area. Without the Boots, Players can never land on platforms and jump to the top.

Example 3

Above is an example of using a Grappling Beam to get to the pink door and acquire Wave Beam. If the players don’t have a Grappling Beam yet, this deep gorge is almost impossible to pass as the bottom is full of deadly spikes and pit blocks, and no halfway platforms are provided. Even though the players painfully avoid the pit blocks and suffer from great health damage through walking on the spikes, they still can’t jump to the doorstep because the height is way out of the player metrics.

Example 4

This left picture is a snapshot of a shaft that is a few screens long. Players start from the shaft bottom, and aim at climbing to the top. Players can’t jump straight to the top as there are no halfway platforms but floating beetles with thick armors. However, once players acquire Ice Beam, they can freeze the beetles to create stepstones to make it to the top, as shown in the right close-up picture.

Example 5

This is a screenshot of a narrow entry high above in the middle of air. To enter the shaft, players need to somehow fly into the tall, narrow gap. Normally, players think of turning themselves into a ball to become one-tile narrow. However, the gap is too tall to be reached as a ball (players can’t jump as a ball). This then convinces players that they need an upgrade for their ability which is Space Jump that allows them to somersault as a ball.

Example 6

Above is an example of how gating is implemented through the environment. Super Metroid has areas segmented by themes. Once the players enter the blue door, they enter an area with a new theme where the high temperature brought by the deadly lava causes constant damage per second unless the players either die or go back and acquire a Varia Suit.

Here is a similar example. This is a snapshot of the Maridia area where water is everywhere so that players can hardly jump or climb throughout the space without a Gravity Suit.

Example 7

Enemies can be gates, too. When players go into a level and encounter a powerful boss that is too strong to be defeated at this stage, the boss works as a deterrent to the players, which encourages them to upgrade the items/abilities and come back.

Above is an example of how a miniboss blocks an area. Players need to defeat this miniboss (whose name is Crocomire) first, otherwise, they can’t explore the following area or obtain the Grappling Beam.

In Super Metroid, enemies as soft gates are usually combined with doors as hard gates. Hard gates lock players in this area so that they prevent players from fleeing when fighting with enemies, while enemies (especially minibosses and bosses) as soft gates lock future areas against players.

Gating Affordances

How does a game make players aware of the gates? And how does a game guide players to open the gates? Hints are essential. The key here is to provide the right amount of clues instead of immediate answers so that players need to think a bit, solve the problem, get the reward, and feel good about their intelligence.

A related term is called Affordance, a word created by James Gibson, an American psychologist. It means the quality or property of an object that presents a prompt on what can be done with the object. In other words, some features are designed to provide subtle instructions to the users.

For example, a doorknob is a protruding part on the door that usually has a different texture or material from the door itself and an ergonomic shape that fits into your palm. It is implicitly yelling at you: “I am grabbable!” In this case, affordances are created by many kinds of contrasts to raise users’ attention, such as depth/space (protruding part), texture/material (metal knob vs. wood door), shape (spherical knob vs flat, rectangular door).

Gating Affordances in Super Metroid

Let’s see how affordances are set up in Super Metroid. This game provides hints from several different perspectives:

• similarity

• difference

• metaphor

• imitation

Similarity

When you see two different things with similar parts, they will catch your attention, and you tend to build a tentative connection between the two parts. Most of the similarity-based hints are designed upon colors.

Example 1

Pink doors need to be opened by Missiles that have a pink bullet on top.

Example 2

Green doors need to be opened by Super Missiles that also have a neon green bullet on top.

Example 3

(Player shoots Grappling Beam to attach and swing)

(When trapped, players connect Grappling Beam to the outlet to electrocute the boss )

The above is also an example of how color similarity is intentionally arranged in the game. When players shoot out Grappling Beam, they’ll notice that the beam has an ice blue color. When players enter the room with the Boss, Draygon, they’ll notice the outlets emitting ice blue currents. This sheds a light on how the boss could be defeated.

Difference

Using differences to create affordances is rather close to the similarity approach, but with one more twist. It is like how artists use negative space to create images. Difference-based affordances allow players to observe the similarity first, then the difference, and encourage players to fill in the blank to solve the puzzle.

Example 1

Here we come to the critical water tube leading to the Maridia area. Many players have been stuck around this water tube, like me, as they keep traversing nearby areas trying to find any unexplored openings but fail to. We wonder: “Why am I stuck here?”

Some players might notice the small platforms above and below the tube, which makes the world outside the tunnel extremely tempting. Some will notice a structure with a similar shade of green nearby. What an odd chance that there is a similar structure that the players have walked in-n-out for several times. Let’s see how similar they are.

I believe this side-by-side comparison explains itself. The structure on the right is actually a tube as well, but it somehow got blasted and has no glass left. What does this suggest to the players? Blast the glass! It is the difference between the two that implies the solution, which in this case is a fill-in-the-blank puzzle.

Example 2

(Player is about to acquire item from the Chozo Statue)

(Player goes to Chozo Statue but nothing is in its hand)

Every time players acquire an item, they get the orb held by the Chozo Statue. However, when players go to the treasure chamber in Wrecked Ship, they see the floor full of spikes and a Chozo Statue with an empty hand. Where is the ball that is usually held by Chozo? What if there is no ball? The solution is to make a ball on your own!

By literally filling in the blank, players activate Chozo Statue by morphing into a ball in Chozo’s hand. Chozo then breaks the spikes and brings players to the treasure.

Metaphor

Metaphor is borrowing a well-known concept and applying it to something new, and quickly make people understand a new system through analogy. Super Metroid also introduces commonly known objects and provides hints to guide players to interact with them.

Example 1

How do game designers make players know that a certain structure is solid outside but hollow and traversable inside? Use real-life concepts. In this case, a water pipe is perfect. According to Nielson Norman's 10 Usability Heuristics, this is the second principle called Match between System and the Real World.

Example 2

Everyone has a mouth. A mouth has space behind the lips and teeth, and the space leads all the way to one’s digestive system. In Super Metroid, there are three monster mouth structures that appear blocked but are actually enterable. When players see the monster teeth, they would instantly be aware of a passage behind. Also, the monsters' mouths add grim uncertainty to the upcoming exploration.

Imitation

Creatures in this game can provide you with hints on paths. By observing and imitating the creatures, players can usually figure out a way in/out.

Example 1

Here we come back to the broken water tube. If you observe the crabs, you’ll notice that some crabs come from below. They would either climb up or climb back down. Look how only half of the crab is above the floor. This indicates that there is a path beneath the floor.

Example 2

This game never explicitly tells you what to do. Instead, they send you creatures to teach you special moves. Players are locked in long shafts before they learn Shinespark and Wall Jump from the creatures, respectively.

Example 3

The moving Geemers (spiky creatures that move along the surfaces) throughout the tunnels will make players realize that this is a pipe.

Conclusion

Super Metroid is a classic textbook for non-linear level design. Many players claim that this game is extremely cryptic. Yes, in some sense, it is. But I believe this is part of the charm here. After hours of being stuck, the moment one finds out the trick would provide chills and bliss that are worthy of the hours.

On top of gating design, there are many more interesting design details that I didn’t have enough time to cover in this analysis. If you are interested and want to get inspired, you may as well try finding the design sparks yourself. I believe after 26 years of release, this game still brings you refreshing insights.