Rush for Diamonds: Hold and Win Slot by Onlyplay

Buy bonus gives you a choice here, and it's a genuine one. For 100x your bet you pick either Free Spins or Diamond Respin - two completely separate bonus paths at the same price. Free Spins play out as standard payline wins with a retrigger mechanic (3 Scatters during the round add 10 more spins on top). Diamond Respin is the jackpot path - diamonds land carrying bet multiplier values, stick in place, and each new one resets the respin counter back to 3. Fill enough of the 20 positions and the four-tier jackpot ladder opens up: Mini at 25x, Minor at 50x, Major at 150x, Grand at 1,000x. Those jackpots only exist inside Diamond Respin. Free Spins won't touch them.

Triggering either bonus naturally takes different symbol counts. Three Scatters start Free Spins. Six diamonds on a single spin start Diamond Respin - a higher threshold, but diamonds appear frequently enough across the 20 paylines that it's not as rare as it sounds. The miner character with his headlamp and bushy beard is the Wild, substituting for everything except Scatters and diamonds. He shows up as the highest-paying regular symbol too, alongside pickaxes, lanterns, dynamite, and a mine cart. The card symbols - J, Q, K, A - glow an electric blue that stands out against the warm amber tones of everything else on the grid.

The mine cave backdrop sells the setting better than most themed slots bother to. Rough rock walls with crystals and raw gems embedded in them catch the light from yellow lanterns hanging overhead. The whole scene has this warm underground glow, like actual lamplight bouncing off stone. The ceiling hangs low with golden light pooling around each lantern, and the grid border blends into the rock face naturally rather than sitting on top of it. A modest max win ceiling is the tradeoff for a hit rate above 35% on a medium-volatility game - wins land often, but the biggest single payout tops out at 2,185x.