Pacman for GEM is an ordinary Pacman game, similar to the original. The difference between this and other implementations is that this one runs in a GEM window on any Atari or compatible machine. It works in any video mode from 2 colours right up to true colour, although extra-low resolutions like 320x200 are not supported (the game doesn't fit on the screen). It's entirely possible to make Pacman work on small screens, however, if the user draws smaller versions of the game graphics.
Pacman also includes sampled sounds effects (all user adjustable) and variable speed. New levels can be made easily by editing the level file.