Originally named 'World Hockey'. Reportedly, a prototype version of this game had all playfield inserts marked as playing cards instead of billiard balls and the accompanying game manual referred to these cards. The flyer states, "For the first time ever, a minimum of 25 seconds is guaranteed for extra ball play! Any ball drained during the first 25 seconds is automatically returned to the shooter!" They mean not "any ball" but only Extra Balls, as clarified in the manual where it is an operator option to adjust the factory default of 25 seconds to be anywhere from 15 to 40 seconds for "Extra-Ball time", not "extra ball-time".