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µCity 1.2


This is µCity (also spelled 'uCity', pronounced 'micro-city'), the open-source city-building game for Game Boy Color.



This game is completely free. Just download the ROM, install a Game Boy Color emulator, and play! The last release of the game should be here:

You can also play on real hardware. Even though the game has been developed using mainly emulators, it has been verified to work on hardware. The game detects how much available space there is and adjust the maximum number of saved cities accordingly.

There are two available ROMs. ucity.gbc is the preferred ROM that you should use. It can save up to 16 cities depending on the memory available in your emulator or flashcart. If your emulator fails to load this ROM because of an unknown RAM size or your flashcart fails to save data, try ucity_compat.gbc. This ROM will only be able to save up to 4 cities, but it is more likely to work in all cases.

Note: A direct port of this game to the monochrome Game Boy isn't possible. This game uses most of the extra RAM that was added to the Game Boy Color, which isn't available in a regular Game Boy. While the Game Boy Color has 32 KiB of WRAM, the Game Boy only has 8 KB, and this game currently uses 30 KB more or less. Only a really limited version of this game with a much smaller map and much fewer features would fit in a Game Boy.


If needed, there is a short manual with instructions for the player here.


An open-source project is a lot worse without documentation! That's why the code has a lot of comments and why there is a highly detailed documentation here. And also because assembly code without comments can't be understood even by the developer who wrote it originally. :)


This game needs a really recent version of RGBDS to correctly assemble the code. It is the only real dependency. This toolchain can be found here:

Follow the instructions in that link to install it in your system.

Once the RGBDS binaries are installed in your system, assembling the game is as simple as typing make in a terminal.

If the binaries aren't installed in any system path, the variable RGBDS of the Makefile has to point at the path where they are located:

make RGBDS=path/to/binaries/

This should work on Linux, MinGW, Cygwin, etc. To remove all files that are generated during the assembly process, type make clean.



Game made by AntonioND/SkyLyrac (Antonio Niño Díaz)



Thanks to:

  • beware: For the emulator BGB (, extremely useful tool used to develop this game.
  • Pan of Anthrox, Marat Fayzullin, Pascal Felber, Paul Robson, Martin Korth (nocash) and kOOPa for the pandocs.
  • Otaku No Zoku (Justin Lloyd) for the Gameboy Crib Sheet.
  • Everyone that has contributed to develop RGBDS over the years, specially Carsten Sorensen, Justin Lloyd, Vegard Nossum and Anthony J. Bentley.


This game is licensed under the GPLv3+ license. You should have received the source code of this game along with the ROM file. If not, the source code is freely available at the following address:

Not all source code files are licensed under the GPL v3+, though, only the ones with the GPL header are. There other source files are licensed under different terms (for example, GBT Player is licensed under the 2-clause BSD license).

The media files (graphics and music) are licensed under a Creative Commons license (CC BY-SA 4.0).

GNU General Public License version 3+

µCity - City building game for Game Boy Color. Copyright (C) 2017-2018 Antonio Niño Díaz (AntonioND/SkyLyrac)

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <>.