It turned out the Game King's endless versatility was also its fatal flaw. In addition to different game variants, the machine lets you choose the base level of your wagers: At the low-limit Fremont machines, you could select six different denomination levels, from 1 cent to 50 cents a credit.
The key to the glitch was that under just the right circumstances, you could switch denomination levels retroactively. That meant you could play at 1 cent per credit for hours, losing pocket change, until you finally got a good hand—like four aces or a royal flush. Then you could change to 50 cents a credit and fool the machine into re-awarding your payout at the new, higher denomination.
Performing that trick consistently wasn't easy—it involved a complicated misdirection that left the Game King's internal variables in a state of confusion. But after seven hours rooted to their seats, Kane and Nestor boiled it down to a step-by-step recipe that would work every time.