Burn 'em Up Slot by Light & Wonder

The real engine here lives in the Free Spins round, and it's tied to a tiered 7's hierarchy: a single red 7, a double 77, and a triple 777. During a free spin, when a winning line lands containing 7's, every lower-tier 7 on that line gets upgraded to match the highest 7 already there. Triple 777 sitting on the same line as a couple of single 7s? Those single 7s morph into 777s and the line repays at the upgraded value. It cascades fast, and big-7 lines stack up in a hurry once the bonus is rolling.

Bonus entry is the magenta "Burn 'em Up" logo scatter landing anywhere on the 5 reels. Three, four or five scatters award 12, 18 or 24 free spins, and extra scatters mid-round retrigger more. The bonus also runs on an upgraded paytable, so the 7's transformations are layered on top of base values that already hit harder.

The other signature is the Mixed 7's line. In the base game and the bonus, any combination of single 7, 77 and 777 landing on consecutive reels from the left pays as a special combo line. They don't need to match each other, which means a low-reel 7 plus a triple 777 on reel three still counts. That mechanic is doing quiet work in the background while you wait for the bonus to drop.

Visually it's a retro fruit-machine setup from Light & Wonder's Barcrest line: cherries with green stems, dewy purple plums, citrus halves, watermelons, gold crowns, and the 7's tier in metallic red enamel with flame outlines. The Joker wild is a cartoon jester face, substituting for everything except the scatter. Animated yellow-orange flames lick all four edges of the grid against a deep red flame backdrop, with the pink-and-purple neon logo riding above the reels.

One honest note: the payback shifts on stake size. Drop below a $2 bet and the math tilts against you in a way that isn't flagged anywhere on the bet panel, which feels like a quietly punishing design choice for a slot otherwise pitched at casual fruit-machine fans.