Game Design Document

Tower Escape

Designed By

Alexander Ryan Shepherd

Table of Contents

Contents I. Overview .................................................................................................. 3

II. Theme .................................................................................................... 3

III. Game Details ............................................................................................ 3

1. GRATIS ................................................................................................. 3

A. Goals................................................................................................. 3

B. Rules ................................................................................................. 3

C. Actions .............................................................................................. 4

D. Transitions .......................................................................................... 5

E. Items ................................................................................................. 5

F. Setup ................................................................................................ 6

2. Game Mechanics ...................................................................................... 6

A. Bottomless Abyss .................................................................................. 6

B. Castle Tower ....................................................................................... 6

C. Crates and Barrels ................................................................................. 8

D. Exit Portal .......................................................................................... 8

E. Platform ............................................................................................. 9

F. Player Character ................................................................................... 9

G. Level Manager ..................................................................................... 11

H. Tower Block ....................................................................................... 11

I. Torches.............................................................................................. 12

J. Trap - Blade ........................................................................................ 12

K. Trap - Fire ......................................................................................... 13

L. Trap - Needles ..................................................................................... 13

M. Trap – Saw Blade ................................................................................. 13

N. Void Crystal ....................................................................................... 13

I. Overview Tower Escape is a 3D side-scrolling platformer where the player plays as a sword and shield

wielding paladin who is magically teleported inside of a dark cylindrical castle tower. The

player must journey to the top of the tower to enter a portal that will return them to their

world. This game will feature minimum of 10 different levels, and the player completes each

level by collecting a Void Crystal or entering the Exit Portal. Along the way, the player must

move over unstable platforms, and they must traverse up to higher platforms while

overcoming traps and barriers. The player must keep moving while the tower falls apart, and

they must avoid dying or falling into the below abyss.

II. Theme This month’s theme is “Everything Falls Apart”, and Tower Escape meets this theme because

it is possible for every part of the castle tower to fall apart. The player influences different

sections of the tower to fall into a bottomless abyss while jumping from platform-to-platform.

When the player collides with a platform, then the outer wall of the tower will fall

downwards into the abyss, and it will take all coupled game objects with it.

III. Game Details

1. GRATIS This below section uses the GRATIS mnemonic to describe this video game.

A. Goals

The player’s goal is to win the game by reaching the portal at the top of the tower. Upon

reaching the portal, the player must enter it to be transported back to their reality, and they

will be notified that they have won the game.

B. Rules

• If the countdown has been completed, then the game begins. When the game begins

the player can control the PC.

• If the PC collides with a platform, then that platform will fall after 0.5 seconds. The

platform falls by commanding its parent tower block object to enter the falling state.

• If the player performs a single jump, then the player may perform an additional jump

while in midair.

• If a block enters the falling state, then it will command any blocks that are directly

below it to enter the falling state. This creates a chain reaction which causes entire

sections of the tower wall to fall into the below abyss.

• If the player collides the PC with a trap’s damage volume or the below abyss, then the

PC will be instantly killed.

• If the player collides with crates or barrels in the sprint state, then crates or barrels

will be destroyed. Otherwise, the crates and barrels block the player from moving.

• If the player dies during a level, then the player may choose to try again.

• If the player collects a Void Crystal, then they complete the level. The player must

complete each level to unlock the next level.

• If the player is on the final level, then the player must collide the PC with a portal to

win the game.

C. Actions

Move The player may move left by holding down the <A> or <LEFT> arrow key, or the player may move right by holding down the <D> or <RIGHT> arrow key.

Jump The player may perform a single vertical jump by pressing the <SPACE> key.

Double Jump The player may perform another jump after performing a single jump. The player must press the <SPACE> key to perform the second jump while in midair.

Sprint The player may perform a brief sprint by double-tapping the <A> or <LEFT> key to sprint left, or they may double-tap the <D> or <RIGHT> key to sprint right.

Slide The player may perform a brief slide by pressing the <SHIFT> key. The PC will be enabled to pass under some game objects by sliding under them.

Collect The player may move the PC through a Void Crystal to collect it. The level is complete once the player collects a void crystal.

D. Transitions

Start Level The Start Level state is entered when the player chooses to begin a selected level. The level is setup at the beginning of this game state.

Lose Level The Lose Level state is entered when the PC is killed. The player will be asked to ‘Try Again’ or ‘Exit to the Main Menu’.

Win Level The Win Level state is entered when the PC collects a Void Crystal or if the PC enters the portal in the final level.

Win Game The Win Game state is entered after the player successfully completes every level in the game.

E. Items

Obviously, in real-life the following items are needed to play this game:

• Gaming Computer (x1)

• Keyboard (x1)

• Game Controller (x1) (Optional)

In game, the following game objects are needed to play this game:

• Bottomless Abyss

• Crates & Barrels

• Exit Portal

• Platform

• Player Character

• Torches

• Tower Block

• Trap - Blade

• Trap - Fire

• Trap - Needle

• Trap - Saw Blade

• Void Crystal

F. Setup

• The Level Manager will load the different tower sections, and every block will perform

four distinct raycasts to store a reference to adjacent blocks. (left, right, bottom-left,

and bottom-right blocks).

• At the beginning of each level, the PC spawns at the bottom, and they are standing

idle on a wooden platform. The PC will not accept user input until a countdown is

complete.

• A countdown is displayed in the center of the screen, and it will count from 3-2-1-GO!

The PC will accept user input, and the blocks will be enabled to begin falling.

2. Game Mechanics The following is a list of entities in this game with an explanation of how they work.

A. Bottomless Abyss

The bottomless abyss is positioned at the bottom of every level. Any game object that falls

into the abyss is destroyed.

How it works

The bottomless abyss is an empty game object which features a box collider component used

as a trigger. The box collider covers the entire x- and z-axis area beneath the tower, and it is

always positioned 10 meters below the PC. If an object triggers the bottomless abyss, and if

the object is not the player then it is destroyed. When the player triggers the bottomless

abyss, then the player loses.

Flowchart

B. Castle Tower

The tower is magically suspended over a bottomless abyss, and it is missing its base because it

fell into the abyss long ago. The tower’s interior features wooden platforms, traps, hanging

tapestries, crates and barrels, and burning torches to improve the player’s visibility.

How it works

The tower is made up of large stone blocks where 30 blocks are snapped together to create a

single cylindrical layer of the tower. Every other layer of the tower is rotated -6 degrees (y-

axis) to create an interlaced pattern. A tower block may feature a coupled platform, torch, or

trap, and the coupled asset falls with the tower block into the below abyss. Furthermore, the

tower can be divided up into section where each section consists of 10 layers. It is possible to

procedurally generate the tower by dynamically loading new sections while the player climbs

up the tower.

Note: A dynamically generated tower for a runner mode is a stretch goal for this project.

Figure 1 – A single layer of the tower with some attached wooden platforms. (Top-down view).

C. Crates and Barrels

The crates and barrels are destructible objects that the player may choose to destroy.

How it works

The player may choose to sprint into a crate or barrel to destroy it. Otherwise, a crate or a

barrel is used as an obstacle to prevent the PC from moving past. If the PC is in the sprint

state when colliding with a crate or a barrel, then the crate or barrel will enter the destroy

state. Furthermore, the player will pass through the crate or barrel as it is destroyed.

Flowchart

D. Exit Portal

The Exit Portal is located at the very top of the castle tower, and it is the player’s way to go

home.

How it works

The PC must collide with the Exit Portal, and the Exit Portal will have a trigger to check for

the PC. If the PC triggers the Exit Portal, then the player wins the game.

E. Platform

A platform is the solid surface that the PC may stand on, and it is coupled to its own tower

block.

How it works

A platform uses a box collider to create a flat surface for the PC to collide with. It prevents

gravity from causing the PC to fall straight into the Abyss. A platform causes its parent tower

block to enter the falling state when the PC collides with it.

Flowchart

F. Player Character

The player character (PC) is controlled by the player, and the player may choose to move,

jump, double jump, sprint, slide, and collect. The player character is sword and shield

wielding paladin that was provided by Mixamo.

Move

The PC is a child of an empty game object named PlayerContainer. The PlayerContainer is

positioned exactly in the center of the tower on the x- and z-axis. When the player provides

horizontal input then the value of the input is used to update the rotation of the

PlayerContainer which causes the PC to move around the inner perimeter of the castle tower.

The player must press the <A, D> or <RIGHT, LEFT> keys to cause the PC to move right or left

by rotating the PlayerContainer on the y-axis.

Animation State Machine – Grounded (Entry)

State Name Grounded => 1D Blend Tree (Idle – Run)

Description Uses a simple 1D Blend Tree to blend between Idle and Run animations.

Condition (Exit) Attack is triggered, OR Slide is triggered, OR Sprint is triggered. & Has exit time is false.

Jump

The PC may perform a single vertical jump when the player presses the <SPACE> key. The

player must be grounded or standing on a solid surface before they may jump. Initially, the

PC velocity is set to 0 on the y-axis. A default value of 1000 is set for the jump height of the

player, and the value used in an Add Force operation on the y-axis of the PC. While in midair,

the player may control the movement of the PC with the movement controls.

Animation State Machine – Jump

State Name Jump

Description Plays the Jump animation clip once.

Condition (Exit) isGrounded = true & Has exit time is false.

Double Jump

The PC may perform a second jump while in midair, but it must be performed after a single

jump. The player must press the <SPACE> key to perform a double jump. A double jump

applies the exact same operations to the PC like a single jump.

Animation State Machine – Front_Flip

State Name Front_Flip

Description Plays the Front_Flip animation clip once.

Condition (Exit) isGrounded = true & Has exit time is false.

Sprint

The PC may perform a sprint while it is grounded or in midair. The player must double tap the

<A, D> or <LEFT, RIGHT> keys to cause the player to sprint in the chosen direction. When the

PC enters the sprint state, then it is quickly moved a in the chosen direction for a brief

amount of time. Any destructible object in the PCs path will be destroyed when the PC

collides into it.

Animation State Machine – Sprint

State Name Sprint

Description Plays the Sprint animation clip once.

Condition (Exit) Has exit time is true.

Slide

The PC may perform a slide while it is grounded. The player must press the right or left

<SHIFT> key to cause the PC to enter the slide state. The height of the capsule collider

around the PC is reduced to enable the PC to slide underneath game objects. The PC is

automatically moved a short distance in the current facing direction. If the PC is underneath

a game object, then the PC will be forced to continue sliding until they are no longer under

the game object.

Animation State Machine – Running_Slide

State Name Running_Slide

Description Plays the Running_Slide animation as a loop.

Condition (Exit) Has exit time is true.

Collect

The PC may collect an item by colliding its capsule collider. The Level Manager will be used

to track collected items.

Death

The PC may enter the death state when it collides with a trap or when it falls into the abyss.

Animation State Machine – Death

State Name Death

Description Plays the Death animation once.

Condition (Exit) Has exit time is true.

G. Level Manager

The Level Manager is a special game object that is included in every level of the game. It uses

the Level Manager script to control and track the player’s progress throughout the level.

H. Tower Block

A tower block is the basic building block of the castle tower, and every tower block can fall

into the below abyss.

How it works

Each tower block is snapped together with other tower blocks to create a single layer of the

tower. At the start of the game, each tower block performs four different raycasts to stores a

reference to the left and right adjacent blocks and the bottom-left and bottom-right adjacent

blocks. When a tower block enters the falling state, it attempts to cause the bottom-left and

bottom-right adjacent blocks to immediately enter the fall state. A tower block enters the

falling state when the PC collides with a coupled wooden platform.

Figure 2 – After a 0.5 second timed delay, the highlighted blocks fall into the abyss when the player collides with

the attached wooden platform.

I. Torches

The torches are positioned on the inner walls of the castle tower, and they provide real-time

lighting to help the player see the scene.

How it works

A torch is a child game object of a tower block, and the tower blocks takes the torch with it

when it falls. The torch features a point light that is used to provide real-time lighting to

objects within the torch’s radius.

J. Trap - Blade

The Blade Trap is a trap where a single blade is pushed and pulled out of a tower block.

How it works

The blade has a collider, and if the PC triggers the collider then the PC is killed. The player

must avoid colliding the PC with the blade. The player may escape some blade traps by sliding

underneath them.

K. Trap - Fire

The Fire Trap is a trap where fire is emitted from its base. A fire trap may be positioned on a

platform or a tower block.

How it works

When the fire trap is active, and if the PC collider with the fire trap’s collider then the PC is

killed.

L. Trap - Needles

The Needle Trap is a trap where needles extend out of the ground and retract into the

ground.

How it works

The trap’s needles have a collider, and if the PC triggers a collider then PC is killed. The

player must avoid colliding the PC with the needles.

M. Trap – Saw Blade

The Saw Blade Trap is a very simple trap where a spinning rotary saw blade is placed on a

platform.

How it works

The saw blade has a collider on its blade, and if the PC triggers the collider then the PC is

killed. The player must avoid colliding the PC into the saw blade.

N. Void Crystal

The Void Crystal is a collectible item that must be collected at the end of a level.

How it works

The PC must collide with the void crystal to collect it. The Level Manager will monitor if the

player has collected the Void Crystal, and it will complete the level after the player collect

the Void Crystal.