Pond Design Document
Pond is an action game that, contrary to its appearance, has distant gameplay roots with games like Space Invaders and Galaga. The core idea is to control and eliminate a constant flow enemy objects before becoming overwhelmed. This is accomplished by means of the core gameplay mechanic: Ripples.
Ripples
This is the central idea behind Pond, the mechanic on which the rest of the game is built. An intuitively touch-based mechanic, ripples are a natural fit for a mobile game app where a touch screen is the primary means of input. Played from a top-down perspective on the surface of a pond, touching anywhere on the screen will result in the formation of a perfectly circular ripple that will radiate outwards from the touch point, fading away after a certain distance.
Gameplay Structure
With the core mechanic in place, the gameplay structure can naturally follow. Like Tetris, Pond is not a game with a pre-defined end – play continues until a lose condition is reached. As gameplay progresses, the background pond water will change color from blue to red. Once completely red, the game will end and a score will be tallied, potentially to be uploaded to a High Score board. Using the water to communicate the player's status is a much better solution than adding some sort of Health Meter – not only does it free up screen space, but it communicates its information in an elegant, intuitive manner. The game's visuals are very simple and saturated in an effort to facilitate visual communication, similar to the graphical style of the Nintendo DS game Electroplankton. To further emphasize the "red water" status, on-screen objects will progressively become darker and more silhouetted, eventually becoming pitch-black just prior to a loss.
Several events will result in the water becoming more red:
– Enemy objects remaining in the pond.
– Special enemy actions.
– Creating ripples.
The pond will inevitably become red without the player's intervention, and the rate at which the pond becomes more red due to the above factors will increase as gameplay progresses. For example, after several minutes of play, one second passing will cause the pond to become several times more red than one second passing within the first minute of play.
To return the pond to a blue state, the player must control and eliminate enemy objects in a skillful manner.
Enemy Objects
Enemy objects will spawn sporadically over the course of play. They will become more difficult to eliminate and will spawn at a continually increasing rate over time. Players will primarily interact with enemies via the ripple mechanic, typically to defeat them. This is to say, a player will tap a location on the screen to generate a ripple that will radiate outwards and make contact with an enemy object.
My approach to enemy design begins with creating an enemy object that interacts with the game's central mechanic in the most basic manner. This object acts as a sort of "standard" or "control" from which I can expand upon, twisting and turning the game's mechanics to achieve the most interesting variety of gameplay possible. This would be akin to a Goomba or Waddle Dee expanding into a Koopa Troopa or Waddle Doo and eventually even more interesting designs. The following list will give an example of the type of variety I'm aiming for:
Normal Tadpole – The most basic enemy. Spawns as a small, circular black dot with a small tail and moves around occasionally. It does not do anything. It can be defeated and despawn when it comes into contact with a ripple. Mostly serves as fodder for combos.
Crawfish – A more aggressive enemy. If the player attempts to create a ripple near it, the crawfish will snap its claws at the player's finger, causing the water to become more red. It must be defeated using ripples generated at a distance outside of its attack range.
Turtle – A regular shelled turtle. It can only be defeated after taking three consecutive hits. Its health status is visually represented by its color, ranging from green to yellow to red. If left alone, it will begin to heal after a short time period, so it's important to focus it down quickly.
Toxic Tadpole – A purple-colored tadpole. A sickly enemy, it will burst into a toxic pool upon defeat, staining a section of pond water. Touching any part of the poisoned region will result in the pond taking damage. The poison will dissipate after a short amount of time.
Water Strider – A quick-moving enemy that is difficult to hit with a ripple. It will dash around the pond in a haphazard manner.
Angry Tadpole – A red-colored tadpole. It is faster moving than a normal tadpole and will only remain in the pond temporarily. If it is defeated by a ripple, an explosive red pulse will erupt from it and cause the water to become more red. If left alone, it will eventually pulse blue and disappear on its own, healing the pond instead.
Dragonfly – A fast enemy that flies above the surface of the water, granting it immunity from ripples. It must be tapped directly to "squish" it, defeating it and resulting in a standard ripple.
Dirty Tadpole – A brown-colored tadpole. It will cover the screen in a trail of pond scum that will block ripples and obscure a section of the pond for a limited time. The player can use his finger to "clean" the pond by wiping the section of the screen covered in scum to remove the effect prematurely.
Frog – A frog that will dive underwater if it sense the player creating a ripple nearby. While underwater, it will appear as a vague, black shadow beneath the water surface, invulnerable to ripples. When it surfaces, the player can touch the frog to "grab" its tongue. The player can then pull the tongue back and let go to cause it to snap back at the frog's face, propelling it in the opposite direction it was pulled. (The distance it travels depends on how far back the tongue was pulled.) When it lands, it will be defeated and cause an exaggerated ripple to spawn.
Chains and Combos
One of the most important gameplay elements is the idea of chains and combos. When an enemy is defeated, it will leave behind a much smaller secondary ripple that can also defeat other enemies. In other words, players can chain extra ripples off multiple enemies for a greater effect and score.
Players are also rewarded for careful, deliberate ripples. The more enemies that are hit at the same time by the same ripple, the greater the score multiplier a player will receive for defeating those enemies. This is called a combo, and it is the primary means by which players will accumulate high scores. These combo multipliers are offset by the fact that every ripple created will actually damage the pond – in order to justify each ripple action, a player must ensure that the ripple can garner enough blue to overcome not only the red deficit created by the ripple itself, but to also move the pond as a whole closer to a blue status. This discourages rampant ripple spam and encourages players to make skillful and purposeful ripples, the idea being to optimize the amount of blue gained per ripple by tapping the empty "epicenter" of a circle of enemies.
Scoring
A scoring system is integrated into the game, represent by a translucent number in the corner of the screen. Points can be earned by defeating enemies. Chains and combos will also affect the points earned for defeating enemies by adding multipliers. Earning points will heal the pond, so your score is a direct reflection of how well you are maintaining the health of the pond. At the end of a game, a final screen will provide a tally of the number of each type of enemy defeated, how many total ripples were created, how long the game session lasted, etc., in addition to the final score. The High Score board will encourage players to beat their own best scores as well as those of their friends.
As players surpass certain point thresholds, the game will "level up" and become more difficult by spawning more enemies, causing enemies to deal more damage, etc. Since there is no level ceiling, the game will inevitably become too difficult and will overwhelm the player. The idea is to survive as long as possible through skillful play and earn the highest scores possible.
UI Design
Even the menus and user interfaces of Pond serve an ulterior motive of subtly reinforcing gameplay mechanics and ideas while being surprising and enjoyable in their own right. In fact, right from the title screen the player’s first prompt is “Touch Screen to Start!”. This results in an enormously exaggerated ripple that fades into the main menu screen. This serves to communicate several ideas: (1) The main means of input is “touching”, (2) Touching results in “ripples”, and (3) Ripples are closely associated with “progression” and “advancement”. Many menu options and selections will also result in visually enticing ripple effects, and most menu screens will allow the player to make ripples on the water, even though they don’t do anything. The point is to familiarize the player with the ripple mechanic that they’ll be utilizing in the main gameplay.
In addition, in an effort to appear both visually enticing and intuitive (and a little playful), a “lily pad” menu system is utilized wherein menu options are represented by touchable lily pads. These lily pads can also be “grabbed” by dragging them across the screen. They can be flung around and will spin and ricochet off one another using realistic physics. It’s the sort of addition that makes navigating the menu a bit more enjoyable while fitting with the visual theme.