Paper Zeppelin Design Document (PZ)
Paper Zeppelin is a game about teamwork and strategy.
PZ is a multiplayer side scrolling shooter where the player(s) fly a zeppelin and attempt to secure, and deliver, a bomb to the enemy’s base in each level.
Each level contains a variety of sky based and ground based enemies, a bomb that must be picked up, and an enemy base that must be bombed successfully to continue.
The game is designed to be simple, with a focus on interacting mechanics.
Bomb – The most important part of PZ, each level contains a Bomb somewhere before the appearance of the enemy base. While carrying the Bomb, the player’s hit box is enlarged, making is far harder to avoid enemy projectiles. Further, their speed in decreased while carrying the Bomb.
Shooting – PZ uses a right stick shooting mechanic, so pointing the stick in a cardinal direction will shoot a bullet in that direction. However, if a player is carrying a Bomb, they cannot shoot downwards.
Medals – Awarded for using the Bomb on a Base and for playing well.
Path – The Levels the players are playing. The Path is based on how many Medals were awarded on the last level. There are 3 Paths, and the players will play different paths based on their performance.
Mission Goal – The Medals /requirements (enemy destroyed ratio/Base Destruction) required to get the Advanced Branch of levels.
Stage Version – Stages have different enemies that spawn depending on how many players are playing. Most enemies will not spawn in single player, and 4 player will spawn all of the enemies in a stage. The engine will use different cues to differentiate the different enemy spawns.
Life Pool – Players all share a common Life Pool so players can drop in and out of a game.
Flying – the left Stick controls the direction of flight. It is analog and variable based on the amount of press on the stick.
Firing – the right Stick controls firing. Holding in a cardinal direction (or close to it) will fire a bullet it that direction at a rate of up to 3 per second.
Bombing – The Triggers allow the player to drop a bomb if they player is carrying one. Either trigger can be pulled.
As a player plays their goal in each level is to reach the Mission Goal by destroying enemies and successfully bombing the enemy base.
The right stick shoots while the left stick controls the flight of the players.
When the player sees the Bomb, they fly into it to pick it up. Then they must continue through the level while being handicapped by the bomb.
When the enemy base appears the player flies over it and drops the bomb. If it hits, then the players are awarded a Medal.
Medals – There are two types of medals awarded in Paper Zeppelin.
Gold – Awarded for Completing the Mission Goal and Destroying the Base
Silver – Awarded for Destroying the Base, but failing the Mission Goal
If the players completes the Mission Goal, then they move up to the next most difficult Path (unless they are already on the Advanced Path – then they stay there). If the players bomb the base, but do not complete the Mission Goal, they will continue on the path if they are on the Middle Path. If they only survive, but do not Bomb the Base then they move down to the next lowest Path (unless they are already on the Lowest Path – then they stay there).
The Mission Goal / Gold Medal requirements do not scale, and are based on a percentage for enemies spawned vs. destroyable enemies that scrolled off the screen.
The player will regenerate some HP at the end of every level.
In single player mode, the player plays through the main game. The stages only have single player enemies activated. Other players can join the Single Player at any time (making the game Multiplayer).
In single player, a death reduces the life total by 1 and the level is restarted.
In Multiplayer Mode, up to four players share a pool of lives. The stages have the multiplayer enemies active (depending on the number of players).
Players can drop out of the game, and their current life is added back to the pool.
In Gunner Mode, two players control each Zeppelin. One player pilots the Zeppelin and the other controls the shooting and the bomb dropping.
In 4 player Gunner Mode, there are 2 Zeppelins.
Each Team counts as a single player for the purposes of Stage Version.
This mode is designed for casual players. There is no drop in/out for Gunner Mode.
Bullets – simple shells that travel across the screen on a specific vector. If they hit a enemy, that enemy loses 1 HP. Player bullets only travel about 1/3 – 1/2 the total screen distance.
Zeppelins – the player avatar. When they are destroyed they make long term crashers that do not burn out.
Lives – Players have a communal pool of lives available. When a player is killed that pool is reduced by 1. The player will respawn if there are lives available in the communal pool.
Most enemies have a specific amount of HP. When a player bullet hits an enemy, its HP is reduced by 1. Some enemies cannot be defeated with bullets, and must be destroyed other ways.
If a player collides with an enemy, they take damage.
Bullets – simple shells that travel across the screen on a specific vector. If they hit a player, that player loses 1 HP. They are destroyed if they hit the ground.
Rockets – Rockets travel in a fixed victor for a specific amount of time, but slower than Bullets. Once they reach the end of their random time, they explode, dealing damage (1 HP) to all players in the blast radius. If a player is directly hit by a rocket, then 2 HP worth of damage is dealt.
Crashers – When enemies or players are dealt lethal damage, they fall towards the ground. Once they reach the ground, or have fallen a certain distance, they are destroyed. Any player, or enemy hit by a crashing object is dealt lethal damage as well.
A falling Bomb is considered a type of Crasher.
Dive Bombers – These enemies travel to the left and go up and down until a player enters their “Dive Zone” – an area below and to the front of them (or above and in front), at which point they will quickly move towards that player in an attempt to hit them. If a player is no longer in their Dive Zone, they revert to their standard movement. They can hit the ground and be destroyed while Diving.
They create short term crashers that can burn out.
Fighters – These enemies travel towards a specific player. Once they enter the screen, they will randomly select a player or select the player closest to the front of the screen. They will then attempt to move up and down to be on the same height as the player. If a player is directly in front of them, or to the direct left, they will fire bullets at that player.
They create short term crashers that can burn out.
Fortresses – These enemies travel across the screen in a straight line. When a player gets close to them, they will target and fire bullets at that player. Once a player has been targeted, Fortresses will not shoot at another player until the targeted player is destroyed or moves outside of their firing Zone. They require several hits to destroy.
They can appear from either the front or back of the screen.
They create long term crashers that do not burn out.
Turrets – Turrets fire bullets at players. They act like Fortresses but have a much larger firing zone. When a player gets close to them, they will target and fire bullets at that player. Once a player has been targeted, Fortresses will not shoot at another player until the targeted player is destroyed or moves outside of their firing Zone. They require many hits to destroy.
Rocket Launchers – These will randomly fire Rockets. When they fire a rocket they will add up all of the player’s X and Y coordinates and find an average. The rocket’s vector will then be based on the average. Bullets deal no damage to them.
Bases – Bases have no offensive capabilities of their own. Bullets deal no damage to them and they can only be destroyed by a Bomb or a Crasher.
The Ground – The Ground also has no offensive capabilities. Running into the ground deals the same damage as running into an enemy. It will also move the player in a direction based on the type of ground.
Destructible Ground. Acts as normal ground but can be destroyed by hits from player’s or enemies.
Gravity Ground. When destroyed creates a Falling Ground Crasher Type Enemy. This crasher type, when hitting either Destructible Ground or Normal Ground becomes Destructible Ground. The Falling Ground Crasher does not destroy the Destructible Ground on contact. Instead they will stack.
The Bomb – The Bomb should be picked up if the player touches it