I made a rail shooter for Kenney Jam 2025 | Maximum Voltage

In 48 hours, I made a Starfox-inspired rail shooter

Sunday, August 17, 2025

Projects:

Maximum Voltage

Practice. Practice. Practice.

Since Scream Jam 2024, I’ve been creating tons of small prototype projects in Godot to better learn the engine’s features. Since I wanted to focus on the coding, I’ve been using Kenney assets exclusively for these projects so I was really excited when I learned that Kenney has a yearly game jam!

Preparation

After not doing so well in my last 7 day jam, I was extremely nervous to try a 48 hour jam but decided to make the best of my time by reviewing Adam Younis’ jam devlogs for tips before the jam. I took away two points from his devlogs: make a schedule and prioritize tasks. To that end, I put together my own general purpose schedule for a 48 hour jam based on my best guess at how long each task would take. The exact time spent on each task isn’t that important but the order I work on them was carefully chosen to get the game playable as early as possible.

Expand schedule

Day	Time	Goal	Actions
Friday	11:00 AM	Ideation	Brainstorming - Concept Design
Friday	12:00 PM	Systems	Mechanics - Core Loop
Friday	01:00 PM	"
Friday	02:00 PM	"
Friday	03:00 PM	"
Friday	04:00 PM	Game Playable
Friday	05:00 PM	World Design
Friday	06:00 PM	Core Animations
Friday	07:00 PM	Game Loop Bookends	Score - Win Condition - Loose Condition
Friday	08:00 PM	Level Design
Friday	09:00 PM	"
Friday	10:00 PM	"
Friday	11:00 PM	"
Saturday	12:00 AM	"
Saturday	01:00 AM	UI Design
Saturday	02:00 AM	"
Saturday	03:00 AM	Game Complete-able
Saturday	04:00 AM	Juice
Saturday	05:00 AM	"
Saturday	06:00 AM	"
Saturday	07:00 AM	Story
Saturday	08:00 AM	SFX
Saturday	09:00 AM	"
Saturday	10:00 AM	Music
Saturday	11:00 AM	"
Saturday	12:00 PM	Beta Test
Saturday	01:00 PM	Collectables/Extras
Saturday	02:00 PM	"
Saturday	03:00 PM	"
Saturday	04:00 PM	Title Screen
Saturday	05:00 PM	Settings Menu
Saturday	06:00 PM	Credits
Saturday	07:00 PM	Cutscenes
Saturday	08:00 PM	"
Saturday	09:00 PM	"
Saturday	10:00 PM	Create itch Page
Saturday	11:00 PM	"
Sunday	12:00 AM	Testing	Test Game in itch
Sunday	01:00 AM	Create thumbnail
Sunday	02:00 AM	Screenshots
Sunday	03:00 AM	Submit
Sunday	04:00 AM
Sunday	05:00 AM
Sunday	06:00 AM
Sunday	07:00 AM
Sunday	08:00 AM
Sunday	09:00 AM
Sunday	10:00 AM
Sunday	11:00 AM	DEADLINE

After building the schedule, I finished my prep for the jam by downloading every Kenney and Kay asset pack and importing them into a file manager called Eagle. Eagle is a program I learned about last year from a YouTube video on tag-based filesystems and I’ve been using it ever since to help organize my game assets (not sponsored, I just really like it). The nice thing about Eagle is that it lets you assign tags to your assets and search for them much easier than through Windows Explorer. I figured having the files indexed would help me find what I need during the jam quicker.

Searching for Kenney and Kay assets in Eagle

Ideation

Before the jam started, I had been on a rail-shooter kick playing games like Starfox 64 and Galaga: Destination Earth. Having seen the ships in the Kenney Space pack before, I really wanted to try making a game like these and was thankful when power was announced to be the theme. Immediately, I decided that I would build a 2-3 minute rail shooter where the player fires electrical bolts and can charge their ship to either unleash a more powerful attack or dodge. I figured this idea was perfect for a short jam since player and enemy movement could be done entirely with Path3D nodes.

Being inspired by retro rail shooters, I also decided the game would run in an extremely low resolution (256x224) and adhere to the simple geometry and colors of a SNES SuperFX game.

Development

Component architecture

I’ve been working to embrace component architecture more in my recent games so I started by defining a whole set of reusable components for every game function I could need: health, hitboxes, hurtboxes, scoring, item pickups, damage/hit effects, etc. These components are so generalized that almost every object in my game was built from the same components.

Most components are also written in such a way that they can take references to other components to chain behavior without needing any code. This is done by having the components self-subscribe to the linked component’s signals on ready. For example, the pickup component will kill a linked health component when obtained and the death component will destroy an object when its linked health component is killed.

Player controllers

Both the player and enemy inherit from a custom PathFollow3D node called RailFollower which adds extra logic to follow a path at a set speed.

The player ship doesn’t directly follow the path but rather is constrained to a 3D plane following the path; unfortunately, it gets a bit more complicated still. I learned that to look correct, the ship actually needs to pitch and yaw away from the camera as it reaches the extents of the screen. That caused problems for the aiming since I implemented the crosshairs as literal 3D objects attached to the front of the ship. Having the ship pitch/yaw as it moves caused the crosshairs to go off screen and required a lot of manual tuning to fix.

Player scene showing the crosshairs in front

Rendering

Several people in the jam comments assumed I was using a shader to pixelate my game but the reality is much simpler. I just set the project’s window resolution to 256x224, enabled viewport scaling, and switched it to integer upscaling. The game is natively rendering in 256x224 and the pixel size just gets multiplied for larger windows.

This has the downside of causing the game to be very small by default; however, I used Itch.io’s canvas size option in the game settings to force the canvas to a larger initial size.

Time allocation

To help with my planning for future jams, I recorded my time throughout the jam:

Expand devlog

Friday
- 11:00: Project setup
- 11:15: Ideation
- 12:15: Rendering
- 12:22: Rail follower / camera
- 13:20: Player movement
- 13:38: Targeting reticule
- 14:32: Bug fix
- 16:00: Hit box / health components
- 17:00: Laser components / spawn manager
- 18:40: Break
- 19:40: Basic enemy
- 20:20: Gameplay tweaks
- 23:20: Break
Saturday
- 00:03: Scoring system
- 01:19: Power system
- 02:44: Break
- 03:16: Add turbo laser
- 04:30: Add boost
- 04:45: Enemy spawner
- 05:00: Trigger volumes
- 05:30: Fixing shader stutter
- 05:51: Game balance
- 06:00: Bookends
- 07:00: Break
- 07:40: Jam page
- 08:05: Break
- 12:38: Bookends
- 16:23: Beta testing
- 17:53: Transitions
- 18:35: Bug fixes
- 18:39: Game over screen
- 21:55: Level design
Sunday
- 00:55: Break
- 01:39: SFX
- 02:55: Visual design
- 03:56: Break
- 04:20: HUD
- 05:49: Splash screens
- 06:43: Credits
- 08:17: Store page
- 10:00: Submission
- 10:14: Fix sound bug
- 10:17: Done

Expand time summary

Task	Details	Minutes
Planning	Ideation	60
Planning Total		60
Project Setup	Godot setup	15
Project Setup Total		15
Core Code	Rendering code	7
Core Code	Shader preloader	21
Core Code Total		28
Mechanics	Movement code	18
Mechanics	Camera	58
Mechanics	Crosshair	54
Mechanics	Projectile system	100
Mechanics	Hit box / health components	60
Mechanics	Drone enemy	40
Mechanics	Power system components	85
Mechanics	Dodge	15
Mechanics	Turbo laser	74
Mechanics	Scoring system	79
Mechanics	Enemy spawner	15
Mechanics	Trigger volume component	30
Mechanics Total		628
Game Loop Bookends	Level reset code	60
Game Loop Bookends	Menu code	225
Game Loop Bookends	Game over code	196
Game Loop Bookends Total		481
Level Design	Level design	180
Level Design Total		180
Beta Testing	Beta testing	93
Beta Testing Total		93
Bug Fixes	Bug fixes	95
Bug Fixes Total		95
Balance	Gameplay tweaks	180
Balance	Score balancing	9
Balance Total		189
Audio	SFX	76
Audio Total		76
Polish	Scene transitions	42
Polish	Visual polish	61
Polish	HUD redesign	89
Polish	Splash screens	54
Polish	Credits screen	94
Polish Total		340
Jam Submission	Itch page	128
Jam Submission	Submission	14
Jam Submission Total		142
Break	Break	514
Break Total		514
Total		2841
Dev Total		2327 (81% of allotted time)

I’ve heard from multiple devs that a short highly polished game will do better in jams than a longer less polished game so I spent most of my time working on polish rather than the game’s level. This unfortunately meant the final level was only 30 seconds long but I think it worked to prove out the concept.

Post-mortem

Results

Of the 717 final entries, I received 22 comments and won best itch.io page.

Given the jam isn’t ranked, I wasn’t expecting to win anything with over 700 other entrants so I was blown away that I won best itch.io page.

The most common feedback I received was that the visuals, polish, enjoyment, and genre choice were great but that the game was too short, hard to determine depth, and the ctrl keybinding was conflicting with browser shortcuts.

You can play Maximum Voltage on itch.io or check out one of my favorite submission to the jam:

Pros and cons

Pros

Components made it easy to build levels and add new behaviors
Kenney assets look great in low-resolution
Focusing on core gameplay first was the right move
High-score focus makes the game more enjoyable to replay
My strength is cinematic events so a rail shooter really highlighted that
Including hit% in the score screen made it more fun to replay
Rapid fire is so satisfying
Early web testing helped identify several critical performance, audio, and sprite issues

Cons

Spent too much time working on the menus and didn’t have enough left to finish the first level
Difficult to tell in editor what the bounds of the player’s movement are which made level design more trial and error
There’s no reason in the final game to use the dodge so it just feels like a waste of power and by extension the single power pickups
Developed the game with my speakers on low so I didn’t notice until after submission the master volume was way too high
Should have made my game manager a general purpose scene transitioner as that would have reduced code in the main menu scene
Ctrl was a bad key mapping - it’s hard to press and I learned from a reviewer that pressing Ctrl+W closes the entire browser
No volume slider
Several people had issues with depth perception
Name didn’t quite match the game
Should have used pictures instead of headers for the jam page, shouldn’t have repeated the title in the page text after the banner
The aim-centering is bugged and re-centers the aim on the ship not the screen making it so your ship blocks the view when shooting anything straight ahead

What’s next

Due to popular demand, I started working on several updates to the game during the judging period. While I’d like to make a full rail shooter at some point, I don’t think Maximum Voltage has enough of an identity of its own for that but I am working to complete the first level of the game as I envisioned. This means adding enemies that shoot back and more cinematic encounters.

I have a lot of jams scheduled back-to-back this year so I won’t make any promises for the release date but know that it is in the works.