They just played the tapes on TV, kinda screechy, computer-y sounds. They'd tell you when to press record on your cassette player before they started. You'd hold it close to the TV speakers until it finished playing, then plug the cassete player in to your computer, and there'd be some simple free game to play. I didn't believe it would work but it did. I still don't believe it worked. But it did.

There must be a clip somewhere on the internet but my search skills are nowhere near good enough to find one.