Apple IIgs

A very select few "IIe" games will detect if they are running on a IIgs or ask the user if they are. These games can use GS/OS features and take advantage of features (or work around compatibility issues) of the IIgs hardware.

95% of Apple ][ series games run on the Apple IIgs. But, some game creators have specifically noted their game will run on a ][gs and is supported.

The original IIgs firmware (ROM01) is the most compatible. ROM03 slightly more compatibility issues.

Games that rely on undocumented features in joystick, paddles, and cassette features are particularly susceptible to incompatibility. Note, a game does not necessarily need to make use of a joystick, paddles, or come on a cassette to rely on the hardware features for them.