Lie Yan Zuan Shi Slot by Playtech

The reels sit in a slab of pure black, rimmed in glowing red neon and licked by orange flames down both sides. The symbols are old casino furniture given a shine: fat lucky 7s in red, blue and green on gold plinths, gold BAR, BAR-BAR and BAR-BAR-BAR plaques, a stack of gold bars, a gold dollar sign, a horseshoe, and one brilliant blue diamond. A classic fruit machine dressed up in fire, basically.

The flaming WILD does the heavy lifting. It stands in for everything except the scatter and pays the most on its own, with the red 7 next in line and the diamond propping up the bottom of the table. Symbols can also stretch to cover more of a reel, so a tall 7 or an expanded wild fills positions a normal icon wouldn't reach.

The scatter is the fiery 烈焰钻石 logo, and it does double duty. It pays wherever it lands, and three or more of them open the free spins. You get ten, and the reason to want them is the multiplier. It opens at 2x and climbs by one every second spin, so it's worth the most late, once it has had time to build. Any wild that lands during those ten spins turns sticky and holds its place for the rest of the round. Catch one early and it rides every remaining spin at whatever the multiplier has grown to by the end.