Role: Game Designer

Merby is a flash game that was developed in four weeks for IAT410: Advanced Game Design. We started by defining a concept, genre, and audience, then we prototyped and tested the game until its completion.

Tools: Flash & AS3, Photoshop, Illustrator, Pen & Paper



We were asked to tailor our game to two BrainHex types. These archetypes define common player behaviours. We knew that our concept involved being underwater and swimming away from a scary angler fish. We also knew we would have a points mechanic and we wanted to use the concept of flow. Therefore, we targeted Achievers, who enjoy conquering and gaining as many points as possible, and Survivors, who enjoy defeating scary threats.


Our mechanics needed to be well documented and prioritized so that we didn't run out of time without having a core mechanic functioning. We split our ideas into a core mechanic, primary mechanic, and secondary mechanic. This was a living document that we updated as we iterated.


Our assignment was to create a game with one key innovation. After we came up with the underwater concept we thought it would be novel if the player had to die to progress. Thus, our innovation is the symbiotic relationship between the main enemy (Miguel) and the main character (Merby). Merby then became a parasite who needed to be eaten in order to gain more points in a risk-reward dynamic.


We needed to run two playtesting sessions for Merby. One with the first working prototype, and one with the second. We gathered 5-7 participants for these tests and ran them through our game to find usability problems or game mechanics that were not working as intended.

We began Merby's development with moodboards and concept art like the piece you see here. We wanted to make a game that was an open-ended system, one that played with concepts of flow, and one that didn't require manually creating levels. We decided to make a game about eating fish where the underwater world was infinite and the fish were procedurally generated.

The Pitch

"Deep at the bottom of the ocean lies your only friend who’s also your worst enemy. In complete darkness, with enemies all around, a lumbering threat appears - it’s Miguel, the angler fish. Merby is a deep-sea, luminescent, risk-taking action arcade game; it's Flow with Paper Moon's art style.


In developing our concept, we took inspiration from many sources. However, we carefully analyzed the mechanics of two games in particular:


From Osmos we took inspiration in the atmosphere, colours, and mechanics of swimming. Osmos uses sound, light, and colours to evoke emotion as well as gameplay mechanic cues.


Flow is a game that heavily relies on the game theory of the same name. It's au underwater game where players eat organisms in order to grow larger. The player can choose when to dive deeper, revealing harder enemies, or surface upwards, to an easier level. We used the idea of eating as well as some of the nuances of their implementation of flow as inspiration for Merby.


After settling on our concept, we set out to prototype our game and prove out some of the core technology. First, we needed a pixel-perfect hit detection system in order to avoid having players accidentally get eaten by Miguel too often. Second, we needed Merby to be able to swim infinitely through the level. Lastly, we needed a system to manage the amount of fish spawning to keep players in a state of flow. Meanwhile, our artists refined the look and feel of the game.


Core mechanic diagram


Hit detection test in Flash


Artist's sketch of characters - Miguel (angler fish, left), Merby (right)


Artist's drawing of enemy type


We targeted two player types as defined by the BrainHex classification system. From their website, BrainHex is a "new player model [that] depicts gameplay behaviour in terms of seven key elements in the human nervous systems - the hippocampus and sensory cortices, the amygdala, epinephrine, norepinephrine, the orbito-frontal cortex, the hypothalamus, and the nucleus accumbens." We knew we wanted to built a deep-sea, risk-taking arcade game, so we chose two player types that would compliment such a game.

Check out BrainHex at



Achievers like collecting anything and everything, and work towards the satisfaction of completion and overcoming distant goals. They like games such as Final Fantasy, Mario, and World of Warcraft.



Survivors like escaping from scary threats and pulse-pounding risks. They love to be terrified and then feel safe again. They enjoy games like Bioshock, Resident Evil, and Silent Hill.



Movement is everything in Merby. The player can cause Merby to move in any direction, for as long as they want. This applies to NPC characters as well - fish, enemies, and Miguel the angler fish. We tuned Miguel to move much more slowly than the other characters, and to gradually slow down as he reaches Merby. This plays on the dynamic of inevitability, and allows players more control over when they want to be eaten. Movement is also how Merby collects fish to feed miguel, and how he dodges enemy fish.


Miguel has a number of mechanics associated with him - some resultant, some operative. Primarily, he always follows Merby. Secondarily, Miguel's light expands when he's fed fish. As a strategy, players can choose to be eaten - see below. This triggers Miguel's operative mechanic: directly controlling him to eat fish and gain points. However, in this mode, his light dims for the entire 15 seconds, lending a risk-reward component to the mechanic of his light. This also creates our main failure state - when the light goes out completely.


Being Eaten

Being eaten is both a strategy and a resultant mechanic - the player chooses when to be eaten to maximize points, but without having Miguel's light dim entirely, and the player does this by allowing Miguel to eat them. This mode is timed for 15 seconds, which creates a timed burst of exciting gameplay. This was designed to support the concept of flow - players choose when this state occurs, unless triggered accidentally, and it creates a temporary rush which moves them up the flow channel.


With Merby, we explored symbiosis and the notion that Merby is a parasite. Our core mechanic was our key innovation - that in order to progress and gain points in the game, the player must perform a risk-reward calculation and choose to be eaten by the game's main enemy. We developed Miguel for the purpose of filling this role, and to add a constant urgency to the game.


Artist concepts for Miguel

Fish & Flow

To keep players in a state of flow, we had to ensure that fish were spawning properly throughout the level. They act as both multipliers for Merby and food (fuel) for Miguel. At one point in development, we added a "bubble" sound to indicate to ourselves when a fish spawn event had triggered. We noticed that people didn't immediately pick up on this subtle cue, so we left it in as a way to randomly generate bubble sounds without over-burdening the player with information on fish spawn points. We also developed an atmospheric BGM track for Merby. Check out some audio samples below.


We tested our game twice with two sets of real players using the think-aloud method. Based on testing results we adjusted fish spawning, UI, tutorials, and more.

Prototype 1

In prototype 1, many players felt that the dominant strategy was to always get eaten by Miguel. There were a few reasons for this. Firstly, fish were spawning outside of the light radius. As Miguel's light got bigger, it actually became more difficult to find and collect fish. We adjusted the fish to spawn outside of the screen instead. To remedy the issue of Merby not feeling useful, we added points multipliers to that Merby could collect fish when he was swimming normally. Some players didn't notice a difference in states (normal vs. eaten) so we added a blue hue to the screen when in points mode. This was designed to brighten the level and make distant fish easier to see, in addition to a state change.

Prototype 2

Prototype 2 feature a more visually appealing UI and a better intro tutorial, to help new players understand the dynamics at play. Additionally, we added a "clock ticking" sound when in points mode to increase the tension and further reinforce that this was a timed event. We further tweaked fish behaviour so that they were attracted to Miguel normally, but some were repelled by him when in points mode. Lastly, we made Fluffy (enemy fish) knock off Merby's points multipliers, if any, before killing him. This would give players a second chance because Fluffies were often difficult to see coming.



Upon testing our second prototype, we found a considerable increase in participants' rated enjoyment of controlling Miguel and of getting points. There is clearly more work to be done to exploit our infinite level concept, because the enjoyment of this mechanic was very low. We noted that many participants wanted more enemy types, increasing difficulty, and generally more variety as the game went on.


Simon Fraser University, Advanced Game Design Project


Jenny Shen, Gavin Stinson, Tia Rambaran, Chris Lu


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