One Hundred and One Monochrome Mazes

Display Support

Since the game runs in 80x25 text mode, it may not be immediately obvious why a monochrome display adapter is required; after all, any color card can support this mode just as well.

The most likely technical explanation lies in the format of the level data. Hidden traps and triggers are designated by a different attribute byte (in video memory) from that of the surrounding floor. On monochrome cards (MDA or Hercules) this difference is not visible on screen, but on CGA or compatible standards, these locations would show as differently-colored characters - which would obviously defeat the purpose.
Source and further reading: 8088mph