Heart of the Frontier Slot by Playtech

There's no scatter symbol in this one. None at all. The whole game runs on two wilds, and everything it does flows through them. The red-haired sheriff and the dark-haired bandit both act as wilds, and when either lands she doesn't just sit in her cell, she expands to cover her entire reel.

Then she stays. Once expanded, the wild locks to the reels and walks one position to the right on every following spin. A single one sweeps clear across the grid over several turns, throwing new wins as it moves, until it finally walks off the right edge. That slow drift is where most of the base-game pay comes from, since a full reel of wild lines up with plenty of the twenty paylines as it passes through the middle.

Get the sheriff and the bandit onto the reels at the same time and they trigger the Showdown free games. Both hero wilds lock in place and duel at high noon, each holding its reel while the spins run, so two full columns of wild sit on the grid together and keep forming combinations. It's the only bonus round the game has. And it's a neat fit for the theme, two walking wilds squaring off instead of the usual pick screen.

No buy button, no jackpot ladder, no wheel. The reels sit in a sun-baked frontier town, weathered wooden saloons with a hanging "Sally's" sign, barrels, a saddle and a longhorn skull off to the sides of a dusty main street. The cast is a glamorous set of Wild West women, a blonde ranch cowgirl with a lasso, a red-dressed saloon girl holding cards, a Native American woman in a feathered headband. Low symbols are worn playing-card royals laid over green, blue and black poker chips.