Dusty Nugget Slot by Genii

Two features sit on top of an otherwise ordinary 10-line setup, and the first one fires straight off the Wild. The blue diamond Wild substitutes for everything except the scatter, but landing any number of them, even a single one, carries a chance to open the Gold Mine Well. When it does, it pays a flat multiplier of your stake with no spinning or picking involved: 5x, 10x or 20x at the low end, climbing through 50x, 75x, 100x and 200x, up to 500x and a top rung of 750x. It is an instant credit drop rather than a bonus mode, so a dead-looking spin with one Wild can still cash out hundreds of times the bet.

The bigger event is the hold-and-win round, and it needs a specific layout to start: two Gold Carts on reels 2 and 3 plus a Gem Cart on reel 4, all three at once. You begin with three respins. Only Gold Coin prize symbols matter from there. Any Gold Coin in view locks in place and stays for the rest of the round, and an Extra Spins symbol landing anywhere resets the counter so a steady drip of coins can stretch the round well past three spins. The values stay hidden while you play. Once the spins run out, every held coin flips to reveal its prize, scaled to the bet that triggered the feature, with the top coin worth 2,000. There is no buy option, so you wait for the carts to line up. A double-or-nothing gamble sits on top of any regular win if you want to push it.

The board itself is mounted in a weathered timber mine frame against a desert dusk, orange mesas and saguaro cacti behind a purple sunset, with loaded mine carts running on rails down both sides and a chain of gold-filled carts crossing the top. A little lizard suns itself on a rock in the corner. Symbols mix studded-metal card royals (gold A, pink Q, teal K, green J) with the themed premiums, a brass oil lantern and an orange XXX moonshine jug among them. It is a clean Klondike mining build rather than a flashy one, closer in spirit to California Gold than to anything tumble-driven, and the scatter quietly pays from three anywhere on top of the line wins.