Knowing the various slot machine types, how to read the paytable, and the odds and probabilities that go along with them can help players make more informed decisions & possibly increase their chances of winning. Different Sluck of the irish slotslot Machine Types. Slot machines come in three primary varieties: progressive slots, video slots, & classic slots. Though video slots are digital and have virtual reels with excellent graphics & animations, classic slots are based on the classic mechanical machines with real reels. A portion of every wager made on a progressive slot machine goes toward a jackpot that builds up until it is won. Progressive slots are connected to form a network.