Game Boy Competition 2021

gbcompo21 was a game jam run from July 1 to October 1 2021 and it was hosted on in new window.

Create original games, demos, homebrews tools and music for the original Game Boy (Color) and compete for glory (and up to $3000+ in prizes)!


Full leaderboards are available here. Top rated entries are playable hereopen in new window while the complete list can be found on Itch.ioopen in new window.


  1. Unearthed
  2. Rhythm Land
  3. Shock Lobster
  4. Dango Dash
  5. Rebound
  6. Core Machina
  7. Sushi Nights
  8. MARLA and the Elemental Rings
  9. Porklike GB
  10. GB Corp
  11. Dawn Will Come
  12. <corrib75>
  13. El Dueloroso
  14. Glory Hunter
  15. Renegade rush
  16. Fix My Heart
  17. GBCspelunky

Winning entry for the Music category: Zilogized

Winning entry for the Tools category: Brainfox


The complete set of entries is available to browse on Itch.ioopen in new window or can be downloaded as a zip file from GitHubopen in new window.



Donations to the prize pool are now closed, no more are being accepted.

The entire prize pool is community funded. Donate or sponsor the competition through GitHub sponsorsopen in new window.

Incube 8 Games

Greenboy GamesCatskull electronicsMega Cat StudiosBitmap Soft1st Press Games

Donations from Individuals

Toxaopen in new window, Carles Castilloopen in new window, Dave VanEeopen in new window, Chris Maltbyopen in new window, William Bettridge-Radfordopen in new window, Josh Frisbyopen in new window, Sanquiopen in new window


GB Studio CentralGB Studio RetroBreak


Come join us on Discord or others for help getting started, and head over to for useful links & resources!

We'd love to hear from participants, share your progress on Twitter using the #gbcompo hashtag and join the conversation the on Discord #compo-chat channel!


Here a curated list tools and documentaiton to get you started.

Prize pool

The current prize pool is $3000+ and will be split according to this documentopen in new window.

Entries will compete in 4 separate categories and 4 rankings will be drawn up. Based on these leaderboards, the top entries will be awarded as follows:

  • Best games (80% of the prize pool)
    • The best 5 games will get a prize.
    • The best 3 OSS games will get an additional prize (can overlap)
  • Best homebrew/tool (1) (running on a GB/GBC)
  • Best music cartridge (1)
  • Best demo (1) (demoscene style demos)

The rankings are decided according to the JUDGING criteria.

Open Source Bonus

If you publish your game source code and assets on a public repository (e.g. GitHub) under an open source licenseopen in new window (GPL, MIT, Apache, CC0...) you get 20% more of the prize as a bonus!

Prize tiers are still work in progress, expect changes. Money prizes are subject to fees and conversions. They may be delivered as gift cards of your choice.


  1. Final entry "deliverable" must consist of a GB or GBC ROM file. You can also attach descriptive documents in TXT, Markdown or HTML file format (e.g. game manual).

  2. The ROM file will be tested on real hardware (usually a DMG or a GBC) and on the BGB emulator. In case of different results, the hardware test will be the trusted one.

  3. GBC features are allowed.

  4. SGB features are allowed. The entries will be evaluated mainly on Game Boy (Color). You can use SGB features, but don't rely on them as main features for your entry.

  5. Teams are allowed (award will be split).

  6. The competition is focused on games, but you are allowed to submit homebrew tools, demoscene style demos and music cartridges. There may be special category prizes for those. There are no preferred themes.

  7. ROM Hacks are not allowed.

  8. NSFW content is not allowed. Please keep it safe for work and avoid anything overly edgy or distasteful.

  9. You can submit more than one entry. They will be rated separately, but each person or team may only accept prizes on behalf of a single entry (e.g., you can't win both the 1st and 2nd place prize).

  10. Judges can submit entries, but they are not eligible for prizes.

  11. Only some official MBC chips (MBC1, MBC2, MBC3 and MBC5, as well as no MBC at all) are allowed. The only exceptions are:

    1. While Nintendo only manufactured very specific MBC+ROM combinations, we will allow any power-of-two ROM size between 32 KiB and the maximum for the chosen chip. (This is simply a convenience feature, as any ROM image can be extended to fit a larger ROM chip by appending copies of itself.)
    2. The ROM+RAM combination (i.e., without an MBC, up to 32 KiB ROM and 8 KiB SRAM), with or without battery, will be accepted for compatibility, as many people have simple flash carts that do have SRAM but don't have an MBC. (This can be trivially emulated by any MBC1, MBC3 or MBC5 configuration.)
    3. The variants MBC30 and MBC1M are accepted, as they have been used in licensed games.
    4. Some official MBCs added extra components to the cart: MBC3/MBC30 carts could have an RTC, and MBC5 carts could have rumble. These combinations, and only these combinations, will be accepted. In particular, this means it's impossible to have RTC and rumble in the same cart.
  12. Entries cannot rely on extra hardware or add-on devices, they must be playable without a specific setup.

  13. As long as you produce a GB or GBC ROM file that runs on GB/GBC, any tool to develop the entry is allowed. This includes RGBDS (ASM), GBDK (C), ZGB (C), GB Studio, ...

  14. Source code is optional, but very much appreciated. Entries submitted with source code (public repositories on GitHub/GitLab/... are accepted) and with an open source license (See rule 15) are eligible for additional prizes. Make sure to fill the "Open Source repository" field with a valid and public repository when submitting on See this issueopen in new window for further details.

  15. To be eligible for the OSS bonus, the code must be licensed under an "Open Source" license (any of the "Free" license listed hereopen in new window is accepted). Assets can be licensed under any of the CC licenses. Obfuscated code, non-reproducible builds, intentionally making the source code hard to read/re-use will exclude the entry form the OSS leaderboards. This is at discretion of the hosts and judges. We must be able to read the code and compile it into a working ROM, running a script or following istructions.

  16. The entry must be submitted on the jam page.

  17. Your work must be new and original. You cannot enter with something you were already working on before the start of the jam. The majority of work should be done during the jam. If in doubt, please ask us before proceeding.
    Examples of things that are allowed:

    • A brand new game using your own (or any) existing game engine.
    • A remake of your (or someone else's) game for a different platform, but with new code and assets.
    • A brand new game you barely started (e.g. you only made a title screen or a mockup of the gameplay).
    • Using templates, tutorial code as starting point (when they're license allow to do so, e.g. gb-boilerplateopen in new window)
    • Asset packs for art and music are ok if the licensing permits. Be sure to make note of what is being reused and under what terms. Use of pre-made assets (vs original ones) may be factored in when judges assess points for relevant criteria (e.g. graphics, audio).

    Examples of things that are not allowed:

    • A project you've been working on for months.
    • An update/patch for a game you already released publicly.
  18. The submission must be available for free for the public (and not only the judges). Submission will be published and kept online for free on the competition website, while you are free to keep working on it (and eventually charge for it/make commercial usage).

  19. Multiple submissions are allowed.

  20. If your submission contains text that isn't available in English, some judges might not be able to read that text, and they will judge accordingly.


Judges will evaluate submissions using the following criteria:

  1. Gameplay - How entertaining are the gameplay mechanics? How fun is the game?
  2. Technical - How innovative is it from a technical perspective? Does it push the hardware to the limit?
  3. Originality - How refreshing is it from a non-technical perspective? Does it have a unique design / mechanics?
  4. Graphics - How impressive are the art, animation and visual effects?
  5. Audio - How good are the music and sound effects?

Criteria applicability:

  • Games are ranked according to all the listed criteria
  • demos on 2,3,4,5
  • Music entries on 5
  • Homebrew/tools entries on 2 and 1 (with gameplay being UX)

The leaderboards are computed by averaging the "Overall" score.


Something not clear? Open an issue or join the discussion on Discord.


Special thanks to:

Full results


Winner: Zilogized by Kabcorp


Winner: BrainFox by Yprit


Sorted by "Overall" score, only the shortlisted entries were ranked by judges.

Rhythm Land3.713.714.143.864.574.0
Shock Lobster4.04.294.713.713.143.97
Dango Dash3.863.293.864.04.573.92
Core Machina3.143.434.04.574.143.86
Sushi Nights3.863.864.03.713.713.83
MARLA and the Elemental Rings3.293.863.434.03.863.69
Porklike GB4.
GB Corp.3.143.864.573.143.293.6
Dawn Will Come2.713.
El Dueloroso3.293.573.863.03.293.4
Glory Hunters3.433.143.433.573.433.4
Renegade rush3.573.573.
Fix My Heart3.712.863.572.712.713.11


Porklike GB4.0
Shock Lobster4.0
Dango Dash3.86
Sushi Nights3.86
Rhythm Land3.71
Fix My Heart3.71
Renegade rush3.57
Glory Hunters3.43
MARLA and the Elemental Rings3.29
El Dueloroso3.29
Core Machina3.14
GB Corp.3.14
Dawn Will Come2.71


Shock Lobster4.29
Porklike GB4.0
Sushi Nights3.86
GB Corp.3.86
MARLA and the Elemental Rings3.86
Rhythm Land3.71
El Dueloroso3.57
Renegade rush3.57
Core Machina3.43
Dango Dash3.29
Dawn Will Come3.14
Glory Hunters3.14
Fix My Heart2.86


Shock Lobster4.71
GB Corp.4.57
Dawn Will Come4.29
Rhythm Land4.14
Core Machina4.0
Sushi Nights4.0
Dango Dash3.86
El Dueloroso3.86
Fix My Heart3.57
MARLA and the Elemental Rings3.43
Glory Hunters3.43
Renegade rush3.29
Porklike GB3.14


Core Machina4.57
Dawn Will Come4.29
Dango Dash4.0
MARLA and the Elemental Rings4.0
Rhythm Land3.86
Shock Lobster3.71
Sushi Nights3.71
Glory Hunters3.57
Porklike GB3.57
GB Corp.3.14
El Dueloroso3.0
Renegade rush3.0
Fix My Heart2.71


Dango Dash4.57
Rhythm Land4.57
Core Machina4.14
MARLA and the Elemental Rings3.86
Porklike GB3.71
Sushi Nights3.71
Glory Hunters3.43
Dawn Will Come3.43
El Dueloroso3.29
Renegade rush3.29
GB Corp.3.29
Shock Lobster3.14
Fix My Heart2.71