The traditional game format is the matching of symbols on the screen or on the electromechanical machine (for the older models).Symbols will vary with the theme of the game, but will typically be personalities, animals, fruits (traditionally) and simple shapes. The symbols will appear on what is referred to as the “payline.” A matching pattern in the payline may offer a prize of some more game credits, or maybe even money.

Most modern slots are “multi-line” machines, which have more than one payline for a given “spin.” A payline is s horizontal line which, at the end of a “spin” indicates which symbols have aligned themselves with it. This permits rapid evaluation of the spin to see if it generated a winner. The traditional reel format machine might have three possible paylines – one in the middle of the window, and one above the middle payline, and one below it. Theme-based video slots can have anywhere from a couple to several dozen paylines. From one to five game credits may be risked on any given payline. The themes of video slots vary widely, from popular movies (like Pirates of the Caribbean and Star Wars) to “legacy” television shows (such as The Addams Family or I Dream of Jeannie), to well-known quiz shows (Wheel of Fortune being the most legendary of them).

One common “format” is a machine called Megabucks. This machine is a progressive jackpot, linked with other Megabucks machines from all over Nevada. In effect, it is more like a lottery. The jackpot starts at $10 million. Megabucks machines have stingier paybacks for all other wins, in order to help amortize the jackpot.