Jamzo Team

The Ultimate Jamzo Mega-Guide

Whether you're a seasoned veteran with dozens of jams under your belt or a newcomer looking to earn your first Elo rating, participating in a game jam is always a thrilling, exhausting, and deeply rewarding experience.

This mega-guide is designed to be your ultimate companion for Jamzo events. We'll cover web builds, game engines, how to prepare, and the secret sauce for great results. Grab a coffee, bookmark this page, and let's dive in.

Why Game Jams? The Ultimate Learning Loop

Before we get into the technical details, it's worth stating why game jams are so important. The fastest way to get better at game development is not by watching hundreds of hours of tutorials or spending three years on a dream project that never sees the light of day.

The fastest way to learn is by executing the core game dev loop: releasing a game -> getting feedback -> implementing that feedback in a new game -> getting more feedback.

Game jams force you to complete this entire cycle in a matter of days. You learn how to scope, how to actually finish a project, and most importantly, you get immediate, honest feedback from other developers playing your game. The more times you repeat this loop, the faster and better you get at game dev. Every jam is a massive level-up for your skills.

The Golden Rule: Web Builds Only

Let's get the most important thing out of the way first. On Jamzo, your game must run in the browser. There are no .exe, .app, or .apk downloads here.

Why do we do this?

Frictionless Play: In a competitive jam with hundreds of entries, players and judges will not download, extract, and run an unknown executable. A web build means a player is playing your game within three seconds of clicking your jam page.
Security: Browsers provide a secure sandbox. We never want our users worrying about malware.
Cross-Platform: Windows, Mac, Linux, ChromeOS - if it has a browser, it can play your game.

Unreal Engine

Unreal Engine is generally a terrible choice for game jams. While Unreal is an incredible powerhouse for AAA desktop and console games, Epic Games officially deprecated HTML5 support years ago. Community forks exist, but the resulting payloads are often massive (50MB+ just for an empty project, and it is very easy to hit 1gb), and performance on lower-end machines is abysmal. If you love blueprints, there are plugins for the other major game engines that do a similar thing!

Test Your Web Build Early

The biggest mistake jammers make is waiting until the final hour to export their HTML5 build. Export a web build on Day 1. Even if it's just a moving cube, get it running in the browser. Export again on Day 2. If something breaks, you'll know exactly which recent change caused it.

Choosing Your Weapon: The Best Engines for Web Games

(Want a deeper dive? Check out our full guide on the Top Web-Friendly Game Engines for Your Next Jam)

If Unreal is out, what should you use? Fortunately, it's 2026, and the ecosystem for web-first and web-friendly game engines is better than ever. Here is a breakdown of the best tools for dominating a Jamzo jam.

1. The Heavyweights: Godot and Unity

If you want a full-featured editor with physics, 3D capabilities, and a massive ecosystem, these are your go-to choices.

Godot Engine (4.x): Godot is incredibly popular in the jam scene. It's lightweight and exports to the web beautifully. Tip: If you are using Godot 4, make sure you use the "Compatibility" rendering method (OpenGL/WebGL2) rather than Forward+. Also, be aware that C# support for web exports is not supported at all in Godot 4. They're working on it!
Unity: Unity's WebGL export is battle-tested. However, Unity games tend to have larger file sizes and longer initial loading screens. Tip: Strip your project down. Go to Player Settings and enable Brotli or Gzip compression. Strip engine code. Do not use high-resolution 4K textures or uncompressed audio. Your goal should be a payload under 20MB.

2. Web-First: Phaser, PlayCanvas, and Three.js

If you are making a web game, you should strongly consider using a native web framework. These output pure HTML5/JS/Canvas/WebGL, meaning load times are practically zero and they integrate perfectly with the browser.

Phaser: The undisputed king of 2D HTML5 frameworks. It is incredibly fast, stable, and has thousands of examples online. It's perfect for arcade games, platformers, and RPGs.
PlayCanvas: A powerful, web-first 3D game engine with a collaborative cloud-based editor. It's essentially the Unity of the web, outputting incredibly optimized WebGL experiences that run smoothly even on mobile browsers.
Three.js: While technically a 3D library rather than a full game engine, Three.js is the backbone of countless web games. If you want total control over your rendering pipeline or are building a highly stylized 3D experience, this is the industry standard.

3. The Visual Scripters: Construct 3 and GDevelop

Not a hardcore coder? No problem. These engines are designed for rapid development and export flawlessly to the web.

Construct 3: Runs in the browser, exports to the browser. It has the best event-sheet logic system in the world. You can build incredibly complex games without writing a single line of syntax. N.b. because games on Jamzo are not monetized, you can use the free version.
GDevelop: Free, open-source, and very similar to Construct. It has a massive library of built-in behaviors (like "Platformer Character" or "Top-Down Movement") that will save you hours of setup time.

4. The Performant Underdogs: Defold and Raylib

Defold: Used by professional studios, Defold is a lightweight 2D/3D engine that uses Lua. Its web exports are tiny (often under 2MB)!
Raylib: If you love coding in pure C/C++ and want to compile to WebAssembly, Raylib is a joy to use. It's barebones, but the performance is unmatched.

Pre-Jam Preparation: Setting the Stage

A successful game jam doesn't start when the theme is announced; it starts a week prior.

1. Prep Your Project and Import Assets Don't wait until the jam starts to open your engine. Have your project created, configured, and working exactly how you like it beforehand.

Strip the Bloat: If you're using a heavy engine like Unity, spend time before the jam stripping out the built-in packages you won't need (like VR modules, heavy post-processing stacks, or unused UI toolkits). This keeps your project lightweight, your editor snappy, and your web export times fast.
Import Your Toolkit: If the jam rules allow it, import your favorite generic assets ahead of time. This includes tweening libraries (like DOTween), input managers, or standard character controllers you've written in the past.
Gather External Libraries: Bookmark color palette generators like Coolors or browse palettes on Lospec. Download royalty-free sound effect packs (like the classic Kenney.nl assets or the WOWIE pack) and have them unzipped in a folder. Set up your favorite synths or trackers (like Bosca Ceoil or BeepBox) so you aren't downloading software while the clock is ticking.

2. Form Your Guild and Build a Team

(For more tips on team dynamics, read How to Build and Manage a Game Jam Team)

Jamzo features a unique Guild system. While you can jam solo, teaming up allows you to pool your Elo and climb the Guild leaderboards. Head over to the /guilds page, find a team with complementary skills (e.g., a Developer, an Artist, and a Composer), and set up your communication channels (Discord, Slack) before the clock starts ticking.

If you are working in a team, establish your workflow before the jam starts:

Version Control: Set up a GitHub repository. Agree on a branching strategy (e.g., everyone works on their own branch and merges into main). Merge conflicts during the final hour of a jam are soul-crushing.
Role Division: Clearly define who is doing what. If two people are writing player movement code, you are wasting time. Have one person handle UI/Audio integration while the other handles core gameplay.
Asset Pipelines: Agree on naming conventions and file formats (e.g., all audio must be .ogg, all sprites must be .png with no spaces in the filename).
The "Bus Factor": Ensure that at least two people know how to build and export the game. If your only programmer falls asleep 3 hours before the deadline, the artist needs to know how to click "Export to WebGL."
Mini Jam!: Have a quick mini jam as part of your team, so you can get used to communicating and working together.

Time Management: Plan for the Time You Have

(Struggling with scope? Read our full breakdown: Game Jam Time Management: Surviving 48 Hours to 14 Days)

One of the most common traps in game jams is looking at the total duration of the jam and assuming you have that many hours to work. Plan for the time you actually have, not the total time available in the jam. If a jam runs for 14 days, but you work full-time and can only spare two weekends, you are participating in a 4-day jam. Scope accordingly.

Here is how your strategy should shift based on the actual time you have available to work:

The 2-Day Jam (48 Hours)

This is pure adrenaline. You do not have time for complex narratives, deep progression systems, or learning a new tool.

Focus: A single, highly polished mechanic.
Strategy: Spend the first 4 hours finding the fun. If the core loop isn't fun by Friday night, pivot immediately. Spend Saturday building out 3-5 short levels or a solid endless loop. Sunday is exclusively for audio, UI, and exporting your web build.
Warning: Do not skip sleep. A well-rested brain will fix a bug in 10 minutes that a sleep-deprived brain will spend 3 hours crying over.

The 4-Day Jam (96 Hours)

Often spanning a long weekend, this length gives your game room to breathe.

Focus: A core mechanic with a secondary layer of depth (e.g., a platformer that introduces a new power-up halfway through).
Strategy: You have enough time to create a proper tutorial and a difficulty curve. Dedicate an entire day to "juice" and game feel.
Warning: It's easy to treat this like a 2-day jam and burn out by day 3. Pace yourself.

The 7-Day Jam (1 Week)

The 7-day jam is the danger zone. It feels like a lot of time, which leads developers to overscope massively, only to realize on day 5 that they have a broken mess.

Focus: A complete, short experience with a beginning, middle, and end.
Strategy: Force yourself to have a fully playable, ugly prototype by the end of Day 2. Spend the next three days creating content (levels, enemy types, art assets). Reserve the final two days entirely for balancing, bug fixing, and polish.
Warning: Feature creep is your biggest enemy here. Stick rigidly to your Day 1 design document.

The 14-Day Jam (2 Weeks)

A 14-day jam is a marathon. It requires discipline and project management skills.

Focus: A polished vertical slice that could potentially be expanded into a commercial release.
Strategy: Spend the first day purely on architecture and planning. Spaghetti code will destroy you in a 14-day jam because you will forget how your own systems work by week two. Take actual days off to prevent burnout.
Warning: Life will get in the way. Plan for at least 3-4 days where you get absolutely zero work done due to real-world obligations.

During the Jam: Tips, Tricks, and Survival Tactics

The theme has dropped. The clock is ticking. Here is how you survive the weekend and produce a winning entry.

The Theme Drop: Brainstorming Your Concept

(Read our full guide on Game Jam Ideas and Brainstorming: Finding Your Hook)

When the theme is announced, your first instinct will be to build the very first idea that pops into your head. Don't. Thousands of other participants just had the exact same idea.

Deconstruct the Theme: Write down the theme word(s). Look up definitions, synonyms, antonyms, idioms, and slang. If the theme is "Light," does it mean illumination? Weight? A match? A lighthearted mood?
The "Aha!" Moment: The ideal game concept should be short in scope but easy to expand. You want to design a mechanic that makes the player have a moment of "Oh, now I get it!" within the first minute of play.
Target a 5-10 Minute Playtime: This is the sweet spot for game jams. If your game is shorter than 5 minutes, it can feel incomplete or like a tech demo. If it takes longer than 10 minutes to beat, most judges simply won't see the end of your game.
Front-Load the Fun: Put your absolute best content first. Don't hide your coolest mechanic behind a 3-minute tutorial or a slow-paced introductory level. Make sure players understand how to have fun as soon as possible.

The "Must Have" vs. "Nice to Have" List

Before you write a single line of code, take out a physical piece of paper. Write "Must Have" on one side and "Nice to Have" on the other, and draw a line down the middle. Put all proposed features in one of the two columns. Focus exclusively on the core experience first. Define your core pillars (e.g., "fast movement" and "one-hit kills") and stick to them. Be brutal here. If a feature doesn't directly support your core pillars, it goes in the "Nice to Have" column - which means you probably won't build it.

Scope Small, Then Cut It In Half

This is the oldest advice in game development, and it is still the most ignored. You are not going to build a sprawling open-world RPG in 48 hours. Think of a simple core mechanic. Now, simplify it further. Your goal is to find the "fun" within the first 4 hours. If your game isn't fun to play with gray boxes, it won't be fun with high-res pixel art.

The "10 Seconds" Rule

In the legendary Bullet Hell Jam of 2021, organizers noted that the best games grabbed the player immediately. On the web, players have zero investment in your game. They didn't pay for it, and they didn't wait 10 minutes for it to download. If they don't understand your game or aren't having fun within 10 seconds, they will close the tab.

Skip the long narrative intro text.
Put the player directly into the action.
Teach mechanics through level design, not walls of text.

Handle Web Audio Gracefully

(Having audio issues? Read How to Fix Web Audio Autoplay Issues in HTML5 Games)

Modern browsers (Chrome, Firefox, Safari) have strict autoplay policies. Audio cannot play until the user interacts with the webpage (a click or a keypress). If your game boots directly into the action, your background music will be muted, and the browser will throw an error in the console. The Fix: Always have a "Click to Start" screen. This single click serves as the user interaction required to unlock the browser's AudioContext.

Juice It or Lose It

(Want more tips? Check out Juice It or Lose It: Adding Game Feel to Your Jam Entry)

"Juice" refers to the non-essential visual and audio flair that makes a game feel tactile and responsive. A simple mechanic can feel incredible with the right juice. (For a masterclass on this, watch the legendary talks Juice It or Lose It by Martin Jonasson & Petri Purho, and The Art of Screenshake by Jan Willem Nijman).

Screen Shake: Add a tiny bit of camera shake when the player shoots, jumps, or takes damage. (Always include a toggle in the options menu to turn this off for accessibility!).
Particles: Emitting a few particles on impacts or jumps adds immense satisfaction.
Hit Stop: Pause the game for 0.05 seconds when a massive hit lands. It adds incredible weight to combat.
Pitch Variation: If your player shoots bullets rapidly, randomly vary the pitch of the gunshot sound effect by +/- 10%. It prevents the audio from sounding like a grating machine gun.

Controls and Accessibility

(For a deeper dive, read Best Practices for Web Game Controls and Accessibility)

Web games are played on a variety of setups.

Stick to standard controls: WASD/Arrows for movement, Space to jump, Mouse to aim/shoot.
Do not use the Escape key for critical gameplay mechanics, as it often interacts with the browser's fullscreen mode.
Do not use Tab, as it will shift focus away from your game canvas and onto the browser UI.
Support both keyboard-only and mouse+keyboard setups if possible.

The Competitive Edge: Maximizing Your Jamzo Elo

Jamzo isn't just about making games; it's about climbing the ranks. After the submission deadline, the rating period begins. Only participants can vote, and your game is judged on four categories: Gameplay, Art, Sound, and Theme.

Here is how to optimize your score across the board:

1. Gameplay (The Kingmaker)

Gameplay is the most heavily weighted factor in player enjoyment. To score high here, your game must be bug-free. A game with one polished mechanic will always score higher than a game with five broken mechanics. Focus on "Game Feel" - how responsive the character is, how fair the hitboxes are, and how smooth the camera follows the action.

2. Art (Cohesion over Complexity)

You don't need to be a master illustrator to get a 5-star art score. What voters look for is cohesion. A game made entirely of simple geometric shapes (like Thomas Was Alone) can score perfectly if the color palette is consistent, the UI matches the aesthetic, and the animations are smooth. Pick a strict color palette (4 to 8 colors) and stick to it religiously.

3. Sound (The Hidden Multiplier)

(Need tools? Check out Free Audio Tools for Game Jams)

Many jammers leave audio for the final hour. This is a massive mistake. Good audio elevates mediocre art and gameplay, while bad audio ruins a masterpiece. If you don't have a composer, use tools like BeepBox to create a simple, rhythmic bassline. Ensure your sound effects are balanced - the player's shoot sound shouldn't deafen the user, and the background music shouldn't drown out the sound effects.

4. Theme (The Creative Twist)

Don't just take the theme literally. If the theme is "Space," making a game about a spaceship is fine, but it's expected. Making a game about organizing the physical space in a crowded apartment is clever. Voters reward creativity and lateral thinking. Take 30 minutes at the start of the jam to brainstorm the most unconventional interpretations of the theme.

The Importance of the Thumbnail

(Learn more: Why Your Game Jam Thumbnail Matters)

Your game's cover image on the Jamzo listing is your marketing. A blurry screenshot will get ignored. Spend 20 minutes designing a bold, high-contrast thumbnail with a clear, readable logo. Look at other thumbnails on different platforms - what do thumbnails that catch your eye do differently? Can you spot any common themes from the ones that you don't want to click?

Conclusion

Game jams are a marathon of creativity, problem-solving, and endurance. By choosing a web-friendly engine, scoping your project correctly, and focusing on polish and game feel, you are already ahead of 80% of the competition.

Remember, your first few jams on Jamzo will mark you as "Provisional" while the Elo system calibrates your skill level. Don't stress about your initial rating. Focus on learning, finishing a game, and engaging with the community. Play other people's games, leave constructive feedback, and celebrate the fact that you created something from nothing in just a few days.

Now, get your boilerplate ready, update your web export templates, and we'll see you on the leaderboards. Happy jamming!