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Monochrome Worlds


Monochrome Worlds is a simple puzzle game where players must help two people reach a common goal. These two people, one of them black and the other white, live in different worlds and must work together in order that both of them reach the gray-colored spot, which is the only place where they can share the same space.

In order to help the other, each character can toggle some of the game’s blocks from one world to the other and back again. This can lead to some interesting situations where a character must remove a block from the other’s world in order to let her companion pass through.

It is a remake, and translation, of a Flash-based game called Monochro Observer created by Tatsuya Koyama. The motivation behind the remake was to be able to play the game in environments that have no Flash players available, such as the GP2X or Dingux. All the design, graphics, and music belong to Tatsuya Koyama, and were used with permission from the author.

Recently i have rebuilt it with Emscripten to bring it back to the web, as i believe that the original Monochro Observer is no longer available. I did not change much of the original C++ code, and it was designed to work on low resolution Linux consoles, that is why it has such a small frame.


  • Left and Right: Move the selected character left or right.
  • Shift: Changes the currently selected character. The selected character will have the blocks of their same color visible and the others invisible.
  • Z: Toggles the block in front of the selected character between the two worlds.
  • X: Undoes the last potentially dangerous movement, such as falling or toggling a block.
  • C: Resets the stage to its initial state.
  • Space: Shows or hides the stage’s tip.
  • Escape: Pauses the game and shows the in-game menu.
More information
Programing language
Made with
Emscripten, SDL
Code license
GNU General Public License v2.0 or later