INTRODUCTION
This document describes a game called "Spiked Acid", which is designed to be a simple, 2D side-scroller, constructed and documented to help others learn to make simple, 2D side-scrollers. The game will employ sprite-based animation, tiled backgrounds, collision detection, phyics, AI, side scrolling & gravity, efficient memory management, render threading, and more basic 2D game techniques.
TECHNOLOGY
Spiked Acid will be developed for the Windows Platform using the McKilla's Gorilla game engine, which is a bare-bones engine developed by Richard McKenna for rapid prototyping 2D games. DirectX will be used as the underlying rendering technology. XACT will be used for all music and sound effects management. Artwork will be brutally simple, and so we'll simply use MS Paint.
BACK STORY
Spike has been working for the Bad Acid Chemical Company since he dropped out of Kindergarten. He knows no other way of life. He knows of no other employment opportunitiies and so he is simply beholden to their every whim. Knowing this, the Bad Acid Chemical Company has decided Spike would best serve their interests as a test subject. The company makes different types of acids as well as acid-protective gear. And so poor Spike lives his life as an acid-test-dummy.
OBJECTIVE
Spike's task is to thoroughly test the Bad Acid Chemical Company's acid-proof suits to make sure they can withstand exposure to some of their deadliest acids. Spike will wear a suit covered in spikes that is also acid-proof. Hopefully, the suit will protect him while he pops balloons floating about the room full of acid. The spikes on the suit will allow him to pop balloons floating above him and next to him, but not below him.
The Bad Acid Chemical Company can be careless, and so they are using balloons that are made of easily corroded materials. As a result, sooner or later the balloons will pop on their own, which would be deadly to Spike. So, spike must pop all of the balloons in the test chamber before the balloons carrode and pop on their own.
GAMEPLAY
The game will work like a side scroller, with Spike able to run left and right, and jump up or down onto platforms and other surfaces such that we may scroll up and down.
Spike will have to be extra careful because there are three different kinds of acids, and three different kinds of suits. Each suit protects Spike from only on particular type of acid. Balloons are color-coded Red, Blue and Green to distinguish between these different acid types, as are the acid-proof suits. Suit protection works as follows:
- When Spike is wearing the Red suit, he is protected from Hydrofluoric Acid (HF), found in the Red Balloons. This is the most dangerous of the three acids to Spike, and will do the most damage.
- When Spike is wearing the Green suit, he is protected from Sulfuric Acid (H2SO4), found in the Green Balloons. This is the second most dangerous of the three acids, and will do the seond most damage.
- When Spike is wearing the Blue suit, he is protected from Nitric Acid (HNO3), found in the Blue Balloons. This will do the least damage to Spike of the three.
To change suits, Spike will have to return to the changing room, which will be his start location. Once in the changing room, Spike can select the colored suit he wishes to wear.
The acid-protective suits have a strange effect on the room and as a result the balloons. And so, depending on the suit being worn by Spike, the balloons will behave differently as follows:
| Suit Color in Use | Red Balloon Effect | Blue Balloon Effect | Green Balloon Effect |
|---|---|---|---|
| Red | No Gravity | + Gravity (sinks) | - Gravity (rises) |
| Green | - Gravity (rises) | No Gravity | + Gravity (sinks) |
| Blue | + Gravity (sinks) | - Gravity (rises) | No Gravity |
CONTROLS
This game will be played using both a keyboard and mouse. Once started, use the following:
- A - Move Left
- D - Move Right
- LEFT-ARROW - Move Left (same as A)
- RIGHT-ARROW - Move Right (same as D)
- SPACE - Jump
- Suit Selection Buttons - Once at the Changing Room Door, the player may select which suit to change into by clicking on the appropriate protective suit button
- ESC - This pauses the game and presents a pop-up window to the player asking them to continue when they are ready. If a game is not in progress, ESC does nothing.
GRAPHICAL USER INTERFACE
As far as the GUI is concerned, if we consider
- Splash Screen - The splash screen GUI simply presents a game logo and a Start button for the user to press when they are ready to play. Upon pressing it, a brief scripted sequence is played explaining a little about Spike and the back story for the game. While playing the message "Press ESC to Skip" should be displayed at the bottom of the screen. If pressed, the game should immediately start.
- In-Game Menu - While the game is in progress, we'll always have a game menu that allows the player to select from the following options:
- New Game - If a game is in progress, first we'll pop up a dialog to make sure the user really wants to quit the current game. If we conclude the user really wants to start a game, then the game state is reset and begun.
- Pause Game - This button is deactivated when a game is not in progress. If pressed, it will produce the same effect as the ESC key.
- Display Controls - If pressed, the game will display an info screen that includes a description of all game controls.
- Best Times - If pressed, the game will display an info screen with the fastest times for clearing the level.
- About - If pressed, the game will display an info screen with information about the game author.
- Exit - If pressed, the game program will exit.
- In-Game GUI - Once a game starts, a 5-4-3-2-1-Begin sequence is counted down and displayed for the player to see. At Begin, the changing room door opens and Spike pops out in his Red protective suit. Balloons will begin to be deployed about the chamber. While playing the following will be displayed at all times:
- Time Remaining
- Popped Red Balloons/Red Balloons Remaining
- Popped Green Balloons/Green Balloons Remaining
- Popped Blue Balloons/Blue Balloons Remaining
ARTWORK
All artwork in the game will be original. The following needs to be created:
- Spike - we'll only dress Spike in his acid-proof gear, so we'll need to make artwork for him in his Red, Green, and Blue outfits. Each will require animations for:
- Walking Right
- Walking Left
- Jumping Right
- Jumping Left
- Jumping Up
- Collide With Floor at high speed
- Taking Damage
- Dying
- Red, Green & Blue Balloons - Simple sprites, each require animations for:
- Floating about the chamber
- Colliding with something below it
- Colliding with something above it
- Colliding with something to the right of it
- Colliding with something to the left of it
- Popping, with acid bursting out
- Changing Room Door - Spike will start the game exiting from the changing room in his Red suit. We will not see the inside of the changing room, just a sliding metal door that opens and closes when Spike walks up to it and presses either R, G, or B. For this, we'll need an animatino of the sliding door opening and closing.
- Ceiling, Floor, & Wall Tiles - The test chamber will have multiple floors and platforms to jump onto and off of. We'll use simple tiles for all walkable/collidable surfaces. These tiles will have to clearly define where the walkable surface is. We'll use straight, dark grey, slightly grooved walking surfaces.
- Chamber Background Tiles - For non-collidable tiles that will go in the background of the chamber, we'll just use a black and white tile set arranged in some pattern.
SOUND EFFECTS
All sound effects will be original. Sounds must be made to coincide with each of the following events:
- Walking
- Landing on a Platform
- Balloon Popping
- Acid Absorbed by Suit
- Acid Penetrating Suit
- Spike Dying
- Time Running Out
- Spike Celebrating Clearing a Level
MUSIC
Game Music will be added when time permits.
Web page created and maintained
by Richard McKenna