Monday, May 11, 2009


I've recently been working with the folks from the Game Career Guide forums, mostly a few people looking to put a game together as a community effort. We've been pitching several ideas, looking to produce a short, simple demo game to see how everyone gets along as a team and what the group is capable of.

One of the ideas I submitted was Doppler, a project that I developed a while back, but one that is fairly interesting. While it doesn't look like we'll be making this particular concept, I would like to share it with anyone who may be reading.

Doppler is an arcade-style scrolling shooter, in the vein of Xevious or Galaga. I came up with the idea one night while considering the state of my brother. Without getting into personal details (which I'm not sure he'd appreciate my sharing), he has limited vision in one eye. I realized that if something were to happen to the other eye, he would be legally blind. That meant we'd no longer be able to share certain hobbies, specifically, video games. It made me wonder what kind of games could be designed for the visually impaired.

In theory, a blind player could play the basic part of this game because the audio cues sync up with what is happening on screen. However, the concept evolved much further to the point where a special 'visually-impaired mode' would be required, rather than just the main game, because there will be other things happening on screen.

What follows is basically the 'pitch' for the game; a short version of the design document intended to explain the entire game quickly to whet the appetites of publishers so they will give you a green light to develop it. It's the fastest, easiest way for people to get the idea too, so... here it is;

Doppler Summary...
Concept: A game focusing on the use of visual/sound cues which must repeated by the player to complete each stage. It is best defined as a rhythm game, but the player has direct control over which cues must be repeated, and must also avoid obstacles that cannot be defeated by this method.

Target Platform: Gaming consoles, via community based development programs (X-Box Live, Wiiware, etc). Console specific details below are given for the X-Box 360 platform.

Basic Outline: The player directly controls an aircraft as it completes precision bombing runs on targets (located at the end of each stage). This craft is not a fighter, but instead a stealth bomber with a radar-jamming node that floats directly in front of the ship. Each vertically-scrolling stage is filled with not enemies, but stationary radar 'drones' that come in 4 different color/sound types (set to match the 4 face buttons of the X-box controller). Each drone has a radius around it that will detect the player and increase his threat level. If the player's threat gauge is filled, the player comes under attack and must defeat enemies while the gauge resets. In order to avoid detection, the player must either avoid each drone's radius, or jam it. This is done by pressing the corresponding face button when the jamming node is within the drone's radius. Advanced concepts expand upon this basic premise.

Presentation: The game focuses heavily on sound cues as well as visuals, with each type of radar having a different sound as the player approaches it. These sound cues also have realistic 'moving' sound, with the pitch increasing as the player approaches and decreasing as the player passes. The visuals of the game do not require photo-realism or even a very realistic approach, but cartoon or cel-shaded visuals are undesirable. A stylized approach is recommended. Music is kept to a minimum due to the emphasis on sound, and is mostly of an ambient nature.

Heritage: Doppler is an evolution of classic vertical-scroll shooters such as Galaxian (Namco, 1979) and Xevious (Namco, 1982). It also has elements of rhythm games such as Dance Dance Revolution (Konami, 1998) and Guitar Hero (Harmonix, 2005), though emphasis is placed on a limited set of sounds rather than musical harmonies. Recent titles that would be viewed as competition include Geometry Wars (Bizarre Creations, 2003) and Ikaruga (Treasure, 2001), although neither possess the passive-aggressive gameplay style of Doppler.

Control Scheme...
Left Stick: Moves the player's craft around the screen. The player has full freedom of movement.

A,B,X,Y: These buttons are used to emit a pulse of radar-jamming energy that will disable an enemy drone's ability to detect the player. The color of the button is the same color as the pulse, which must match the color of the drone the player wishes to jam.

R Trigger: This uses the player's Unlimited-use counter-measure or weapon (if in Combat mode).

L Trigger: This uses the player's ammo-based counter-measure or weapon.

L + R Bumper: By depressing both bumpers at the same time, the player activates his 'super' ability.

Basic Concepts...
Scoring: The player is awarded an increasing number of points for completing each level, with bonuses for various achievements, such as completing the level in one life, collecting a number of special items, or avoiding detection entirely. In addition, the player scores points for each radar drone jammed, with more points being awarded for getting closer to the drone without crashing into it. These different levels of scoring are visually represented as rings within the radius of the drone's radar range.

Difficulty: The game includes three different difficulty levels; Easy, Medium, and Difficult. A training mission (Stage 00) that can be skipped is also included which walks the player through the basic concepts of the game. The main differences between these difficulty levels are:

1. Points: Players are rewarded more points in easy mode, while the difficult mode rewards less.

2. Node:
The distance between the player ship and the jamming node is increased in easier stages, making it less likely the player will crash into a drone while trying to get closer for a higher scoring jam.

3. Weapons:
The blast radius of the chaff grenade and the number of homing missiles launched decreases with the harder difficulty levels.

Advanced Player Concepts...
Combat Mode: If the player's threat gauge is filled, the aircraft has been detected and attack aircraft are sent to eliminate him. The player enters attack mode and is able to shoot. The player must survive this onslaught until his threat gauge is completely drained, at which point the enemies stop appearing and the gameplay returns to the normal 'radar jamming' concept.

Counter-Measures: Players have two types of counter-measures; one which is unlimited use, and another which has a limited amount of uses (restored by gathering icons during gameplay). The unlimited counter-measure is an air-brake, which slows the rate at which the stage scrolls, giving the player a longer reaction time. This brake will 'burn out' if the player holds it too long, however. The ammo-based counter-measure is a chaff missile which, when launched, completely nullifies all detection areas in it's blast radius. The size of the blast radius increases in easy mode, and decreases in difficult mode.

Weaponry: Players also have two types of weapons for when they enter combat mode, and like counter-measures, one is used for free while the other has a limited amount of ammo (restored in the same fashion). The unlimited weapon is a rapid fire laser cannon which can be used to defeat enemies. This weapon will overheat if it is used too much without pause. The ammo-based weapon is a homing missile cluster which launches a cluster of 2 missiles that seek out the nearest enemy. On easy difficulty, 3 missiles are launched, while only a single missile is launched on Difficult level.

Super-Ability: In addition to the weapons and counter-measures, the player can consume multiple uses of the Ammo-based item to generate a special effect. In normal jamming mode, the player becomes completely invisible and cannot be detected for the duration of the effect (but can still crash into objects). In combat mode, the player has an "EMP Bomb" that greatly increases the speed at which the threat gauge decreases.

Advanced Stage Concepts...
Mountain Surfaces: Impassible terrain sometimes appears in the form of mountains or walls that the player cannot pass through. Hitting one of these surfaces will result in player death.

Spotlights: Un-jammable detection area that slowly pans across the level. If the player enters the area of the spotlight, his threat is increased substantially for as long as the player stays within the spotlight area. These features cannot be destroyed.

Stationary Guns: These turrets are ground based and fire shots blindly across the level where the enemy thinks the player might be. The shots will result in player death, but can be avoided easily as they are fired at a steady pace. These features cannot be destroyed.

Stationary Rockets: These turrets are ground based and fire player-seeking rockets. The color of the launcher and missile designate what type of pulse will disable the rocket; the player must match the color of the rocket in order to disable (and thus, destroy) the rocket. The launcher cannot be destroyed, but the rockets can be if the player is in Combat Mode.

Chaff Cannons: Like the Gun Turrets, the Chaff Cannons are ground based and fire steady shots into the air. However, the projectiles of these cannons explode in mid-air and leave behind a cloud of Chaff that clings to the player's ship and increases the amount of threat generated whenever the player misses a jam or somehow causes his threat gauge to increase.

Proximity Mines: These floating objects are stationary, with a detection radius similar to the Drones. However, if the player enters the radius of the mine, it will explode, causing a loss of player life. These items can be destroyed if the player is in Combat Mode.

Weather Effects: Stages can take place in 1 of 4 condition types; Day, Night, Fog or Storm.

Day: The detection radius of all drones is increased.
No special conditions.
The detection radius of all drones is decreased, but colors are more subdued and harder to see.
Storm: The detection radius of all drones is decreased, lightning flashes raise threat level.

Recon Ships: Flying craft, manned by human spotters, that slowly flies through the stage. If the player enters the detection radius of this craft, his threat level is instantly filled to max. This enemy can be destroyed if the player is in combat mode, and can be blinded with Chaff.

Ammo Cannister: This type of friendly item contains a special item the player can obtain simply by running into the cannister. Items include (but are not limited to):

Score x2: Any points the player scores are doubled. Lasts 30 seconds.
Score x3: Any points the player scores are tripled. Last 30 seconds.
Ammo: Grants the player an additional use of his ammo-based Counter-measures or weaponry
Extra Life: Grants the player an extra life.

Mod Cannister: This type of friendly item contains a special ship modification that will remain with the player until he loses a life or replaces it with a different modification. Note that this detail can be removed if it is deemed superfluous. These items include (but are not limited to):

Extended Node: Increases the distance between the pulse-generation node and the nose of the ship.
Heat Sink: Increases the overheat gauge for the Airbrake / Laser Cannon.
Camouflage: Increases the Threat Meter, so it takes longer to fill.

Conceptual Artwork...

(Conceptual gameplay screen shot, showing player interface)

(Conceptual gameplay screen shot, showing game elements w/ explanations)

That about wraps it up. As you can see, it's somewhat of a fleshed out concept that I think is pretty much ready to be developed realistically. Feel free to leave any comments you like.