1
Introduction
1.1
Overall
The game is a 2D side-scrolling beat’em’up with a focus on knockback,
knockup and knockdown delivered by the player’s steam-powered arms and legs.
Most of the levels consist of fighting through hordes of enemies and utilizing
the varying knockback from each attack. Visually and gameplay-wise the aim is
to be as bombastic as possible in a 2D space while still maintaining responsive
player control with instantaneous input registering and fast animation. While a
lot of beat’em’ups have a few enemies at a time, the aim is to allow for things
like downing a row of 10 enemies with a well-placed punch.
1.2
References and inspiration
I draw a lot of inspiration mainly from 2D
sprite based game companies and developers. Vlambeer have provided many great
ideas on making a game feel good both visually and gameplay-wise with their
games Nuclear Throne and Super Crate Box. Said games have snappy and simple
controls and nothing about the player’s movement feels sluggish or
unresponsive. They still have visual flair and spectacle though, with the
screen sometimes filling with projectiles in Nuclear Throne. Most of the time
this adds to the game feel and only in rare cases does it become distracting.
A surprisingly good game feel can be found in
One Finger Death Punch. Every time you send an input the game’s reaction is
instantaneous and the animations do the same. The game can thus deliver fast
paced action without the player ever feeling that the game is to blame for a
death. Only two buttons are needed to play: left and right. This kind of
simplicity does have its perks, as a really complex control scheme does
understandably put a lot of gamers off.
2
Development
tools and technologies
2.1
Technical implementation
Unity is
the engine of choice, as it provides a good 2D toolkit that only got better
with version 5. The engine is easy to use and accommodates rapid prototyping
really well. While the ability to port to other platforms easily is a nice one,
the initial focus is PC. If selling the game is ever considered, the free
version of Unity can be used without fees or royalties until a treshold of
$100 000 annual revenue is passed. Input is given digitally with either a
keyboard or any controller with a D-pad and 2 action buttons.
2.2
Graphical assets
Graphically
the aim is to use raster sprites, since they can be downscaled to a certain
point to boost the performance, whereas it’s harder with vector graphics. The
attack animations should convey the punch or kick directly in the first frame,
only using the remaining frames for smoothing. This ensures that the player
attacks instantly when he wants to, and the attack detection is much easier to
handle. Flash Professional CS5.5 is used to create the rough animations, which
are then either cleaned up in the same program or with a raster painting tool
like Manga Studio 5.0. If necessary, outlines may be done traditionally in ink
and scanned in for coloring.
3
World
design
3.1
Setting
The game is
set in a western frontier town and the surrounding desert. In the wake of the
industrial revolution, steam power has seen widespread adoption, mostly for
mining. Massive mining robots and exoskeletons were a boon for the industry, but
they soon found a use in more dubious circles. Outlaws found these constructs
to be easily repurposed as mobile fortresses to control the area. As a
response, the law had to do the same, elevating the traditional shootout at
sundown to an all-out war between bronzen machines of destruction.
Steam
machines have found their uses in everyday life as well. These powered
creations have given the protagonist new life in the form of prosthetics.
Geared towards mobility and overall surpassing of the regular human body, these
new limbs give him the power to perform superhuman feats e.g. jumping to new
heights and giving pesky outlaws a free ticket to the next county with charged
up punches.
3.2
Enemies
The enemies
mostly consist of outlaw grunts. The most basic ones only use melee weapons
like pickaxes or firearms like revolvers. These enemies are considered
throwaway enemies in that the player will usually dispatch them rather easily.
They only pose a threat in big hordes. Harder variants include specialized
enemies such as ones equipped with dynamite or gatling guns. They tend to
require nailing down a certain pattern, such as jumping over gatling gun bursts
or hitting the dynamite back before it blows up.
The real
challenge is delivered via boss enemies wearing steam-powered exoskeletons and
eventually piloting giant, mobile, steel fortresses. These bosses and
minibosses always bring with them a new combat pattern or interaction to learn.
As the player can respawn and try again pretty much instantly, they can easily take
a few tries to get through. They use existing interactions with the combat
engine e.g. knocking grunts back to hit an artillery piece on the other side of
a ravine or knocking grunts upward to unbalance a walking fortress.
3.3
NPCs
The NPCs
mostly play a supportive role, selling the player upgrades to their gear or new
gear altogether. They are mostly found in towns, which the player can access
between levels. They can also be rescued from the outlaws in certain missions
for monetary and gear rewards.
4
Gameplay
4.1
Main game mode
The game plays out in two different screens:
the map screen and the action screen. The map screen is a top-down view of the
land and acts as a hub to all the different missions and levels in addition to
the towns. The action screen means the missions themselves. The aim is to beat
all the missions with various objectives and bosses.
4.2
Controls
The game is
controlled mainly with a keyboard, but as the game handles only digital input,
a controller should work easily too. The only buttons needed are for the
movement, and two action buttons: one for jumping and one for attacking. An
example control scheme could use the arrow keys for movement, the X key for
jumping and the C key for attacking.
4.3
Movement
The
movement works in a traditional platformer style. In addition to moving
horizontally, the player can also jump, crouch and, by extension, slide by
crouching while moving. The horizontal movement doesn’t have any inertia, so
the player starts and stops moving instantly.
4.3.1
Jump
input buffering
To avoid
the platforming becoming annoying, the player can jump a few frames after they
break contact with a platform. This allows for long jumps being worked into the
level design without them becoming too much of a challenge or feeling unfair.
It also allows the player to press jump just as they see theirselves landing on
the ground, even if the engine still thinks they are in the air.
4.4
Combat
All
different movement states have attacks in different directions where possible,
as seen below. This is to ensure that the player has a good amount of control
over his character and doesn’t feel frustrated with limiting attack directions.
An attack
always stuns the enemy for a few frames, keeping them from getting sucker
punches through in-between the player’s attacks.
4.4.1
Attack
input buffering
To allow for basic attack combos, the player may buffer attack inputs. This means that the
player presses the attack button to initiate an attack, then presses it again
while the first animation is playing. This then triggers the next stage of the
combo and the player may continue on like this. This also works when
transitioning from a preanimated combo to another attack.
4.4.2
Combos
Combos
refer to chains of attacks executed in rapid succession. This includes buffered
attack combos and also basic attacks chained together to keep enemies stunned.
Anything that damages or knocks an enemy back, up, or down counts toward a
combo. This might be used at some point for powerful special attacks, but for
the first version it just adds a multiplier to gained points.
4.4.3
Hit
points
The player
and the enemies have a certain amount of hit points, which protect them from
getting knocked back. These don’t regenerate over time, but the player does
regain them with long enough combos.
4.4.4
Dizzy
After the
player’s or an enemy’s hit points are depleted, they enter the dizzy state. In
this state they are vulnerable to a knockback. For a player this means that a
full enemy combo will knock them out, triggering a respawn. For an enemy,
however, this means that any player attack will send them flying a certain
distance through the air, knocking down any enemy they pass through. After
landing, they are knocked out and despawned.
4.4.5
Knockback,
knockdown and knockup
A big focus
of the game is the ability to knock dizzy enemies around and use them as
projectiles of sorts. This can be used to knock down other enemies, or to
damage bosses from range. This also adds a strategic element to the gameplay,
as area-of-effect attacks with the ability to stun or knockback enemies can be
used to control hordes of enemies.
4.5
Points and money
In score
attack modes, the player is rewarded points for each attack and damage
delivered. The points awarded are always increased according to the multiplier
calculated from the combo count. Enemy knockouts also award points. This is
replaced completely in the story mode with money that the enemies drop. Money
can also be found in crates, chests and other containers scattered about.
4.6
Upgrades
The player
can use the money he gathers on missions to upgrade his gear back at town.
These upgrades provide new abilities or upgrades to existing ones. The new gear
also changes the player’s appearance to reward him further.
5
Screens
The main
game consists of two primary screens: the map screen and the action screen. The
map screen contains a visual representation of the area and acts as a level
select. The action screen contains the core gameplay. The shopkeepers in town
have their own shop screens, showing item statistics, monetary info etc. The
main menu only needs to contain buttons to start the game, to change options
and quit the game. This is because the map screen already provides a space in
which the player isn’t required to react to things in real time.
6
Testing
Testing
will mostly be carried out by letting friends and other students play the game.
This is because the game doesn’t have all that many complex moving parts,
reducing the risk of a killer bug to ruin the whole experience. Of course,
after release, the game will be kept up to scratch, issuing bugfixes and
hotfixes when needed.
7
Distribution
Depending
on if the game gets to a point where selling it would be appropriate, it will
first be released on itch.io. The site provides a quick and easy system for
hosting free games or selling them. Upon checkout the buyer is always
recommended to donate extra money if they want to. This creates a goodwill
system, where the downloader can decide if the game is worth money. Of course,
you can set a baseline price that they must pay to gain access.
If the game
is to be sold, the Humble Store, GOG.com and Steam are always good options. The
only real barrier might be the Greenlight system on Steam. The 100€ fee for it
is rather negligible, but to get on Steam, the developer is required to do a
fair bit of PR in the form of advertisement be it on a development blog or
Twitter for example.
