Quick Hit Slots are so popular because of the available progressive jackpot (but there are games without this offer). A progressive jackpot means that the payout for a winner becomes larger each time the game is played, but the jackpot is not won. When a lucky player gets it, the jackpot is decreased to the basic level and will start growing again each time the game is played without it being claimed. The accumulated amount is displayed at the top of the page when a gambler is playing.
The condition for a big win is getting 5 similar symbols on any of the reels. The probability is random. The player is not able to manage it. The jackpot can become as high as 7500x the value of a bet.