A downloadable game for Windows, macOS, Linux, and Android

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It's time to put your Game Boy collection to work!

GB Corp. is an incremental / idle game for the Game Boy, that rewards you for playing it on several console models.

The core gameplay is quite simple. You hire consoles from the Game Boy line (Original GB, GB Pocket, GB Color and Super Game Boy), and they work for your "push-button" company. When you have earned enough money, you can hire more employees, and upgrade the ones you have so they bring back more income. Also, you must be careful of their power levels: change the batteries of your employees when they are empty!

While the concept is quite simple, this game also has a unique feature: the consoles you hire are effectively working only when you run the game on the same console model! So, to put your GBC employees to work, you need to play the game on an actual Game Boy Color (or set your emulator to "GBC mode"). If you want to make your GBP employees active instead, you'll have to unplug the cartridge and put it into a Game Boy Pocket from your collection (or change your emulator settings). The game uses a SRAM save, so the game progress is kept while switching consoles.

This "console change" is a real gameplay mechanic and not a simple gimmick. When you only have a handful of employees, changing batteries isn't a burden. But when you employ dozens of them, it costs loads of money. However, when you switch from one console model to another (say, you switch the cart from a GBC to an original GB), all the active employees get a new set of batteries for free!

How to play

The game controls are quite simple :

D-Pad : select employees

A : recharge batteries

B: upgrade employee / hire a new employee (if the cubicle is empty)

SELECT : fire an employee (warning, it costs money too!)

START: hold the button for 3 seconds to reset the SAVE (warning, all game progress will be lost forever!)

Each time you upgrade the level of an employee, or hire / fire someone, the cost of these actions increase. However, the more experienced your employees are, the more money they bring! For more precise numbers, each active employee will generate twice its recharge cost (the $number in bracket after the current power level) per second.

Do I really need several Game Boy to play this?

The best way to play this game is on a Flashcart with a collection of different Game Boy models at your disposal (at least 2, but if you only have 1 it'll work too, although you won't be able to benefit from the "free charge" bonus). The game is saving your progress automatically every second, so don't worry about losing any progress when switching the cartridge from one console to another.

But if you don't have a Game Boy at home, you can also enjoy the game ROM on an emulator. I heavily recommend you to use BGB: https://bgb.bircd.org/

In the emulator settings (Right Click > Options), on the "System" panel, you can configure which type of GB model must be active. Each time you modify the setting, you'll have to hit the "Apply" button, and then to reset the emulator (press * on your keyboard). That way, you can easily change from one console model to another.

Technically wise, the game relies on a MBC5 mapper for maximum compatibility with emulators and flashcarts. But as you can see from the small ROM size (32kb), it actually doesn't require a MBC but only 8kb of SRAM to run. So far, I have only been able to test the game with the original Everdrive-GB. But it should work on all flashcarts, including the ones that only feature 32kb of ROM + 8kb of SRAM.

Behind the scenes

This game is programmed 100% in C with the wonderful GBDK-2020: https://github.com/gbdk-2020/gbdk-2020

The great music "In The Town" is composed by krümel (crumb)#0723, under a public domain license (GB Studio Community Assets):  https://github.com/DeerTears/GB-Studio-Community-Assets/tree/master/Music

If you want to try your hand at making Game Boy games, I'm releasing this one as open-source with heavily commented source code (see downloads or the GIThub repo). If you have any question about the source code, feel free to contact me!

This game was created from scratch for the Game Boy Competition 2021: you'll find a lot of cool new GB games to play here!



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Click download now to get access to the following files:

gbcorp.gb [ROM file - use with any GB emulator] 32 kB
gbcorp_source.zip 28 kB


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I love this game! I'm curious though, how is it able to tell between the dmg and pocket? I could've sworn they were the same hardware-wise lol. (except for smaller form factor ofc.)

edit: punctuation


To be honest, the low level hardware detection is performed by the SDK i use: GBDK-2020 https://github.com/gbdk-2020/gbdk-2020

The test itself is made at startup: https://github.com/gbdk-2020/gbdk-2020/blob/develop/gbdk-lib/libc/targets/gbz80/... (see __cpu variable)

Basically, the boot rom is slightly different and leaves the values of some register in different states at startup, and that's how we can detect which GB model we are running on (for DMG / Pocket / Color / Advance detection). For the detection of SGB, it's different: we ask to enable some SGB only features (such as mutliplayer support). If the machine replies a with specific value, then it's running on a SGB, else it does nothing meaning it's not running on a SGB but on another Game Boy model.


hello dr ludos, look days ago i discovered that i saw a page where they sell gameboy plates of i think 500 kb with battery, so with that you could make bigger gamboy games if you want

Really awesome concept but if the game is saving every second you should warn folks not to play it on carts such as the EZ Flash Omega that try to save directly to the SD card - for those carts, you are meant to wait a number of seconds after saving before powering off the system, otherwise the SD card will be corrupted. If the game is constantly saving there won't be a safe point to turn the system off.

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Hi, thanks for the kind words, and for the warning!

I only have an Everdrive GB (1st model) at home, and it doesn't have any issue with this as it saves the SRAM content on SD cart only when we are loading a new rom. But if you have a Flashcart that writes directly the SRAM contents on the SD card, yes, it definitively can be an issue I guess.

The current version of the game doesn't have a pause feature, but I'll add it for a next version so people with such a FlashCart can "disable" the SRAM writes to avoid corrupting the SD card.

Regarding the EZ Flash Omega, can it run GB/GBC roms? (as it's a GBA flashcart if I'm not mistaken). If no, I don't think this device will be able to run the game: to run this game on a GBA you should run it from a "Game Boy" Flashcart so the console switches to the "GBC" mode instead of the GBA one.

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Yeah even though it's a GBA cart it has a modified version of Goomba built in so it can load *.gb/*.gbc files directly, which also saves directly to the SD card. Adding an option to disable the SRAM writes sounds like a great idea for users with some of the weird flash carts out there


any chance we can get a physical release of this game?!?!?

Hi, thanks a lot for your interest! 

I do intend to keep working on this game (for example, adding new GB models), and then yes, I'd like to make it available in physical format. I've already released 2 GB games on cartridge  in the past few years, so I'll try to do it for this game too!


Add the Gameboy Light option please!!!


The Gameboy Light is basically a Gameboy Pocket with a light. Something like this I highly doubt it can happen.


YES!!! I would be all in if you made a physical copy. I have an original GB, GBC, GB Pocket, GBA SP, and a Super Game Boy.  I know it's an undertaking, but IF you ever make this a physical copy, I don't know how I can get on a list to be notified, but I would like to be the first one signed up LOL. Best of luck and continued success!!!

Woaw, thanks a lot for your support, it's motivating! :)

If I manage to push this project up to a physical release, I'll announce it on my newsletter. You can subscribe to it from here: Dr Ludos releases newsletter

Also, I post early beta versions and in progress information of all my homebrew projects for my supporters on Patreon: https://www.patreon.com/drludos


How about you add GBA support? The newest GBDK version should have it.

This is a very good idea indeed! I wasn't aware the newest GBDK did have this feature, thanks for telling me, I'll look into it! The game is compiled with the 4.0.4 version of GBDK-2020, as I didn't want to update the SDK a few days before the deadline to avoid "breaking stuffs, but now I'll take time to update and explore the 4.0.5 version!


There should be an is_gba variable or something like that.

I've checked the latest version, and there is indeed a is_gba variable now. Thanks a lot for the heads up, I'll definitively use it to add GBA support in a future version of the game :)!


You could also add support for the SGB2 using a similar method to Tetris DX to detect the SGB2.

Yes, I do plan to try to add SGB2 support too in the future :)

(first I need to get an actual SGB2 to test if everything is working well :p)


What a  very special game! :o
Tried it on emulator for  a short time. Will play in on real hardware tomorrow! :)

Thanks! I hope you'll enjoy it on real hardware too :)


Absolutely. Played it for a while and it became one of my favorite gbcompo games!  :)

Woaw, thanks a lot for your feedback, it's really motivating to keep doing such games :)