The pinout of that 68K Game Shifter, however, does not match the Shifter IC in any of the Atari ST computers. But incidentally, the never released Atari Panther was to be a Motorola 68000 based game console. Furthermore, the Panther prototype board features a chip conspicuously marked 4118!
So after the cancellation of the Panther development in 1991, I may well be first person for 25 years to be looking at the design of its shifter chip.
I’m a sucker for these kinds of stories. Great work!