Because the trapped Alley ball, once freed, is delivered to the shooter lane and not to the playfield to join the other ball in play, a multiple-ball play situation is not automatically 'forced' upon the player. Therefore, 'Mad World' is not considered a multiball game in the sense in which the term is commonly used to identify games having multiple-ball play as a programmed feature of game play and not instead the player simply shooting more balls onto the playfield. Placing two balls onto the playfield for simultaneous play on 'Mad World' is the option of the player, as can be said for the many games produced from the 30s through the 60s that come equipped with multiple balls all deliverable only to the shooter lane. According to Bally's parts catalog, Early Production games for Mad World had their steel back doors mount directly into a wood groove in the backbox but during production a steel retainer was installed into the wood groove for the rest of the production run. Likely inspired by the 1963 Hollywood action comedy movie It's a Mad, Mad, Mad, Mad World.