Introduction

Summary:

"A casual 3D arcade-style SHMUP with Bullet Hell vibes set in Space --dodge enemy fire, upgrade your loadout, and safely deliver 'Big Bomb' so it can obliterate the alien mothership, thus saving Earth from annihilation."

Motive:

Despite their mesmerising beauty, most Bullet Hell games are overwhelming for the casual player.

I want to create a Bullet Hell SHMUP where the player feels powerful, like they're running a hot knife through butter.

A game the player can pick up and get satisfaction out of while on their commute or sitting in a waiting room, but does not demand huge chunks of their time to progress.

Audience

• Ages 8+
• Commuters
• Students
• Retro/Arcade fans

Goals:

• Make it easy to play on a mobile device.
• Give the player as much choice as possible to play how they want to play.
• Bring some form of narrative to it, to build the world and set the player in an environment with context and feelings of grand achievements.

Design Challenges:

• Satisfying experience within 5 to 10 minutes of play.
• Frequent positive feedback loop.
• A progression system that can be achieved at a comfortable rate; rewarding but not frustrating.
• Just enough danger of death to keep the player from idling when fully upgraded.
• No artificial difficulty like scaling hp of enemies or over pricing upgrades.

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Narrative

"Embark on a mission to save Earth by infiltrating alien supply routes and delivering 'Big Bomb' to destroy their mothership."

Simple, explicit, no time to waste.

Campaign mode contains an intro that sets the premise visually and via the use of text.

The rest of the story is told via cut scenes:

• introducing the boss after mission completion.
• defeating the boss, delivering 'Big Bomb' and destroying the mothership.
• returning to Earth and celebrating the win.

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Game Modes

• Campaign: Story-driven progression culminating in a boss fight. Gather resources for upgrades.
• Casual: Pre-generated levels for casual long-play. No resource gathering, level speed selection.
• Replay Boss: Unlocked upon defeating the Campaign boss.

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Core Mechanics

Intuitive and satisfying, with simple controls, and exciting upgrades.

• Movement: Smooth strafing left and right.
• Shooting: Automatic firing of equipped weapons.
• Shooting: Enemies fire unique fixed patterns.
• Hazard: Boss's cannon fires throughout all three Game Modes.
• Survival: Avoid the Boss's cannon projectile and enemy fire while protecting 'Big Bomb'.
• Survival: 'Big Bomb' takes high damage if enemy units collide with it.
• Resources: Automatic loot collection and conversion to credits upon win/death.
• Upgrades: Spend credits to enhance weapons, armour, and thrusters (strafe speed).

Economy Mechanics

Players collect resources dropped by enemies to purchase upgrades and enhance their loadout.

• Three resource types converted into credits upon win/death:
  • Research Data: Helps Earth advance its technology and gain a tactical advantage.
  • Raw Materials: Used in manufacturing and repair.
  • Dark Energy: Alien energy stores help Earth power gigantic machines and space craft.
• Retry system allows reclaiming lost resources upon death.
• Credits are spent on upgrades, see: Loadout.

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Gameplay Loops

Campaign

• Play intro cutscene
• Load Campaign level
• Attack waves of enemies/obstacles
• Collect resources and health
• Avoid the Cannon
• Default loadout?
  • Yes:
    • Loot boxes trigger weapon swaps
• Pause
  • Resume
  • Select Loadout
  • Adjust volume
  • Quit to Main Menu
• Complete Level
  • Convert resources to credits.
  • Select Loadout
  • Continue to Boss encounter.
    • Play Boss intro cutscene
    • Load Boss battle
    • Attack boss
    • Collect resources and health
    • Avoid the Cannon
    • Pause
    • Win
      • Convert resources to credits
      • Continue
    • Die
      • Retry
      • Quit to Main Menu
  • Quit to Main Menu
• Die
  • Convert resources to credits
  • Select Loadout
  • Retry and collect lost resources
  • Quit to Main Menu

Casual

• Load randomly selected level
• Attack waves of enemies/obstacles
• No resource gathering, just health
• Avoid the Cannon
• Pause
  • Resume
  • Select Level Speed
  • Select Loadout
  • Next Level
  • Adjust volume
  • Quit to Main Menu
• Win
  • No resource conversion just congratulations
  • Take a break message
  • Next Level
  • Select Loadout
  • Retry
  • Quit to Main Menu
• Die
  • No resource conversion
  • Select Loadout
  • Retry
  • Next Level
  • Quit to Main Menu

Replay Boss

• Load Boss battle
• No resource collecting, only health
• Attack Boss
• Avoid Cannon
• Pause
  • Resume
  • Select Loadout
  • Retry
  • Quit to Main Menu
• Win
  • Replay
  • Quit to Main Menu
• Die
  • Retry
  • Quit to Main Menu

Loadout

Default

• Player Armour Level: 1
• Bomb Armour Level: 1
• Primary Weapon: Dual Cannon
• Secondary Weapon: None
• Thruster Level: 1

Upgrades

• Player Armour Levels: 2,3,4
• Big Bomb Armour Levels: 2,3,4
• Thruster Levels: 2,3
• Primary Weapons:
  • Dual Cannon: Default weapon. Two parallel straight streams of projectiles.
  • Hyper Plasma: Rotating Dual Cannon combined with Plasma plume.
  • Quad Cannon: Four streams of projectiles, fanning out ahead of the player.
  • Blitz: 5 sets of Dual Cannons rotating back and forth, spread out in a half spiral pattern.

• Secondary Weapons:
  • Spiral: Rotating 360 degree spiral of projectiles.
  • Sweeper: 180 degree horizontal waves of projectiles.
  • Cross Sweeper: 180 degree vertical waves of projectiles.
  • Ultima: Wide wall of projectiles like a column pouring out in front of player combined with 360 degree scattering projectiles.

Game View

• Faux isometric-orthographic, using a side-on perspective with the player on the bottom left and enemies coming from top right.
• Classic HUD overlay with health in top left and resources bottom right
• Camera pans left or right (up and down on-screen) according to player reaching left and right limits, panning back to the centre when the player is within limits. This helps the player feel less hemmed in.

Art and Effects

The visuals are designed to immerse players without overwhelming them.

A low-poly retro arcade aesthetic, enhanced by neon colors and subtle bloom effects, featuring:

• SEGA Master System colour palette.

• Colour palette serves as a universal texture for all objects.
• Basic arcade style UI and HUD.
• Environment: stars in the background and giant cosmic gas plumes in the foreground.
• Screen shake on explosions/death/Boss Cannon.
• Plasma/laser weapon effects.
• Units explode in debris upon destruction.
• Units drop glowing loot orbs that seek the player to assist in collection.
• Heal and Damage feedback:
  • Player and 'Big Bomb' health bars in HUD.
  • Floating green '+' and red 'x' emitted by player and 'Big Bomb'.
  • Player and 'Big Bomb' bodies flicker red.
  • Low health red overlay screen flicker and Alert sound effect.
• Resource collection feedback:
  • Rotating resource icons in HUD.
  • Count increase in HUD.
  • Floating text every 5k.
  • Award sound effect every 5k.

Maintaining a subtle feeling of cosmic horror with the following details:

• Campaign intro depicts a massive fleet near Earth, this moment illustrates the mothership's scale as it sits behind the fleet.
• Environment includes a swirly gas/smoke pattern, the plumes engulf the scene to make the player feel small.
• 'Big Bomb' trails tightly behind the player and is larger than any unit on screen until the Boss, implying a vastly larger target and imminent doom if it explodes.
• The Boss is overbearing, so large it does not fit on the screen, and can only be defeated with end-game weaponry.
• Boss's cannon fires a massive projectile through the level with a foreboding targeting laser pattern between shots. Until the player encounters the boss they have no idea where this is coming from.
• The final cutscene depicts the mothership being destroyed, only now with 'Big Bomb' hurtling towards it, and the player flying away from it, does the player finally get a feel for just how massive the mothership is.

Level Design

Level Generator

• Maps are stored as 512x512 PNG textures with pixel colours corresponding to units.
• Spawns rows of enemies that move towards the player.
• Level speed, unless overridden by player selection, changes based on weapons equipped.
• Level speed consists of the rate-of-row-spawn and the enemy unit movement speed.

Layout

• Campaign level is hand-crafted.
• Casual levels are generated then tweaked by hand.

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Aesthetics

• Visually pleasing enemy spawn patterns; group the spawns into shapes to create illusion of structure, just enough to stimulate the imagination.
• In the campaign intro the mention of your mission involving fighting your way through the 'supply routes' of the alien fleet is a gentle nudge to the player's imagination, combined with the spawn grouping patterns this should create an industrial feel to what they are seeing.

Obstacles & Pick-ups

• Boss Cannon firing on a fixed pattern with random targeting laser positions to confuse the player.

• Chaos Orbs strategically placed throughout the map, when destroyed they cause an AOE force that destroys surrounding units.

• When the player has the default loadout (default 'dual' primary, no secondary weapon) the loot boxes trigger a timed weapon swap.
  • Epic loot boxes equip primary weapons.
  • Legendary loot boxes equip secondary weapons.

Unit Design

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Player

• Fighter craft, launched from a Space station
• Thrusters but no burners
• Focused on weaponry and being a small target.

Big Bomb

• Constantly rotating and a curved surface to help deflect colliders.
• Reinforced outer shell.
• Thrusters with reserved burners for final delivery.
• Focused on robustness until planned detonation.

Enemies

Supply Transport

• Carrying resources including power, food, and critical personnel.
• Does not fire if friendly unit in front.

Artillery

• Equipped with quad cannons and medium armour.
• Does not fire if friendly unit in front.

Kamikaze Drones

• Fly in defensive formations to shield the fleet.
• Often fly in large groups to pummel 'Big Bomb'.

Sentinel

• Heavily armoured and fully automated gun ship.
• Fires in all directions, does not harm friendly units.

Chaos Orb

• Highly volatile payload used to cause wanton destruction on the ground.
• Risky to transport so they often preceded by Sentinels.

Boss

• Design derived from giant squid, the fins and arms that extend give an effect of blooming tentacles about to intimidate and ensnare their prey.
• Built for maximum armour and damage output.
• Movement pattern is fixed, predetermined.
• Multiple bullet patterns and colours that cycle according to a timed selection.
• Rotating extended arms that fire projectiles.
• Core weapon that fires projectiles in patterns as well as the Cannon.
• 4x Cooling Rails that glow as they heat, indicating the Cannon charging, when fully lit the Cannon fires and they reset for the next charge.
• Massive health pool, each arm destroyed deals its maxHP as damage to the boss.
• Destroying all the rotating arms will allow damage to the core. The player has to discover this as there is no way HQ could know such information prior to the encounter.
• Core weapon and rotating arms are protected at first by a shell. Shell is discarded during boss intro cutscene.

Mothership

• Ominous structure in the distance.
• Brutalist design, minimal details, implying a fortified HQ.
• Rotate entire ship very slowly to accentuate the massive scale.
• No battle encounter, only cutscenes.
• Destroyed by 'Big Bomb' once the Boss is defeated.

UI

HUD

• Player and Big Bomb icons accompanied by classic Health Bars top left.
• Resource icons and count in bottom right.
• Boss icon and health bar appears in bottom centre to the left of the resource icons.
• Pause button bottom right after the resource icons.

Main Menu

Title scene with a 3D text title at the top, Player spaceship in the background firing its Dual Cannons.

When an option is selected the Boss's cannon fires through the game title, the game title explodes, screen shakes.

• Campaign
• Loadout
• Casual
• Replay Boss
• Quit
• Credits

Loadout Menu

• Icons for Armour and Thrusters.
• Animated GIFs for weapons.
• Highlight equipped Thrusters/Weapons.
• Prices below each item.
• Total available credits in bottom right.

Pause Menu

• Level Speed selector on the left. (casual mode only)
• Menu on the right:
  • Resume
  • Loadout
  • Retry
  • Next Level (casual mode only)
  • Quit
• Audio controls below.

Player Died Menu

• Campaign Only: Resource icons and gathered counts on the left.
• Campaign Only: Conversion animation to credits on the right.
• Inform the player 50% of their resources can be collected on retry.
• Menu below:
  • Retry
  • Loadout
  • Next Level (only appears in Casual Death Menu)
  • Quit

Level Complete Menu

• Congratulations message.
• Campaign Only: Resource icons and gathered counts on the left.
• Campaign Only: Conversion animation to credits on the right.
• Menu below:
  • Loadout
  • Continue
  • Next Level (only appears in Casual Death Menu)
  • Quit

Boss Defeated Menu

• Congratulations message.
• Campaign Only: Resource icons and gathered counts on the left.
• Campaign Only: Conversion animation to credits on the right.
• Menu below:
  • Continue

Win Game Screen

• Planet Earth celebrating.
• Credits rolling.

Credits

• Credits roll from bottom of the screen upward.
• Tapping the screen or pressing Esc key returns to Main Menu.

Sound

Design

• Subtle Sci-Fi UI sound effects.
• Arcade blasters/explosions/collections/alerts.
• Dreamy yet lively music at a pace that does not overstimulate.
• Relaxing music for the main menu and pause menu to allow the player to decompress while remaining in game.

Resources

• GDC SONNISS Game Audio Archive
• https://opengameart.org
• https://freesound.org/

Main Menu / Pause Menu
Tsorthan - "Doubt"